President Trump and the leaders of Mexico and Canada struck last-minute deals on Monday to postpone the imposition of hefty tariffs on goods exported to the United States, averting at least temporarily a damaging trade war that would roil North America and the global economy.

Canada’s prime minister, Justin Trudeau, after speaking twice by telephone with Mr. Trump, said U.S. tariffs on his country’s goods would be postponed by 30 days as negotiations on a border deal took place. That announcement came hours after Mexico negotiated a similar delay, agreeing to send thousands of troops to the U.S.-Mexico border.

The frenzy of last-minute maneuvering demonstrated Mr. Trump’s willingness to use tariffs as a source of leverage against the most important U.S. trading partners, inwhat he called an effort to curb drug smuggling and illegal immigration. Imports from Mexico, Canada and China — a target of tariffs still set to take effect just after midnight — account for more than a third of the products brought into the United States each year.

After his call with Mr. Trudeau, Mr. Trump wrote in a social media post that he had agreed to the pause “to see whether or not a final Economic deal with Canada can be structured.” Mr. Trudeau, in his own social media post, described measures that were already being enacted under its $1.3 billion border plan, including the deployment of additional technology and personnel to “ensure 24/7 eyes on the border." He said the two countries would also establish a joint strike force to combat organized crime, fentanyl and money laundering.

Earlier Monday, Mr. Trump said that he would likely discuss the tariffs with China’s leader, Xi Jinping, within the next 24 hours. He described the 10 percent tariffs that he planned to impose on Chinese imports as an “opening salvo.”

China was still preparing its response on Monday. Its ambassador to the United Nations, Fu Cong, said on Monday that China was filing a complaint with the World Trade Organization over Mr. Trump’s tariffs and would consider retaliatory action.

Border motivations: Mr. Trump signed executive orders on Saturday to impose tariffs of 25 percent against Mexico and Canada, with a partial carve-out for Canadian energy and oil exports, and 10 percent against China. The president said he would impose the tariffs until the countries alleviated the flow of migrants and drugs, particularly fentanyl, to the United States. The tariffs threatened to raise the cost of online goods while the possibility of a far-reaching trade war roiled markets around the world.

Mexico’s reprieve: Ms. Sheinbaum said during a news conference in Mexico City that she had reached the agreement with Mr. Trump after a “very respectful” conversation. Under the deal, Mexico received a one-month delay and a promise from the United States to help stanch the movement of guns back over the border, Ms. Sheinbaum said. Both leaders sounded optimistic on Monday: Ms. Sheinbaum said she was sure the coming month would yield “good results,” while Mr. Trump wrote in a social media post that he looked forward to taking part in further negotiations.

Focus on fentanyl: In calling for the tariffs, Mr. Trump highlighted the need to stop the flow of fentanyl, a potent synthetic opioid, into the United States. The president raised the “drug war” with Mr. Trudeau in their call on Monday morning, but far less of the drug comes into the country from Canada. Last year, U.S. Customs and Border Protection agents intercepted about 19 kilograms of fentanyl at the northern border, compared with almost 9,600 kilograms at the border with Mexico, where cartel mass-produce the drug.

President Trump and the leaders of Mexico and Canada struck last-minute deals on Monday that postponed for 30 days the imposition of 25 percent tariffs on goods exported to the United States. The arrangements at least temporarily averted a trade war.

Here are some of the details.

Deploy to the U.S.-Mexico border 10,000 members of the Mexican National Guard, a militarized force tasked with security operations and, in recent years, migration enforcement efforts. The deployment is in addition to the mix of police forces, Mexican Army soldiers and guardsmen already patrolling the border. The National Guard troops will be focused on curbing the flow of fentanyl and illegal migrants into the United States.

Establish two high-level working groups with U.S. officials, including one on security and another on trade. Ms. Sheinbaum said that the agreement also included U.S. action to prevent the trafficking of high-powered weapons into Mexico; Mr. Trump made no public mention of such a promise on Monday.

Continue to implement a spending plan at the border launched in December, worth 1.3 billion Canadian dollars, or $900 million. That figure includes the cost of two extra Blackhawk helicopters, 60 U.S.-made drones and other technical equipment that Canada deployed at the border last month.

Continue, under that spending plan, to bolster personnel at the border. On Monday Mr. Trudeau said that would include stationing 10,000 “frontline personnel” at the border. It was not clear how many officials are already operating across the vast Canada-United States border, which, at over 5,500 miles, is the world’s longest.

Redouble its efforts to tackle the opioid crisis — one that kills Canadians daily — by establishing a new position for a fentanyl czar, committing 200 million Canadian dollars to fresh intelligence gathering on cartels and criminal drug gangs and listing those groups as terrorist entities.

Emiliano Rodríguez Mega reported from Mexico City and Matina Stevis-Gridneff from Toronto.

Canada secured a 30-day postponement in the application of U.S. tariffs on its exports on Monday afternoon just hours before they were scheduled to go into effect after a call between Prime Minister Justin Trudeau of Canada and President Donald J. Trump yielded a border deal that seemed to satisfy both leaders.

Mr. Trudeau had earlier pledged to retaliate against U.S. tariffs by imposing tariffs against U.S. goods, too. In the end, he seemed to make modest concessions to Mr. Trump on the border policies, including thousands of “frontline’” personnel stationed at the border.

“I just had a good call with President Trump," Mr. Trudeau said in a social media post that laid out the terms of the agreement. “Proposed tariffs will be paused for at least 30 days while we work together.”

The deal brought relief and de-escalation into what had turned into a brewing trade war between the two close allies and top trading partners, although its 30-day horizon did indicate that more negotiations might need to take place down the line.

Specifically, Mr. Trudeau said that Canada would create a new position for a fentanyl czar and redouble its efforts to tackle the opioid crisis — one that kills Canadians daily — by listing cartels and gangs as terrorist entities, like Mr. Trump has said he wants to do in the United States.

Canada would commit 200 million Canadian dollars, about $139 million, to fresh intelligence-gathering efforts around the fentanyl and drug trade, Mr. Trudeau said.

He also said that as part of the agreement with Mr. Trump, Canada would continue to implement a new border-tightening plan that it had announced weeks earlier.

That involves the expenditure of $1.3 billion Canadian dollars in fresh funds over the next several years, the deployment of new technology at the borders and the deployment of more border guards.

“Nearly 10,000 frontline personnel are and will be working on protecting the border,” Mr. Trudeau said in his post without elaboration.

The government has already deployed police officers to the border in recent weeks and some provinces have started patrols with sheriffs and conservation officers. While the head of Canada’s military has said that it is ready to deploy troops to the border, it was not immediately clear if that will now happen.

Canada last month added two Blackhawk helicopters and 60 U.S.-made drones to its border surveillance program.

In last-minute meetings in Washington last week, top Canadian officials presented the results of the tighter border surveillance, as well as the implementation of stricter visa rules for migrants.

Mélanie Joly, the foreign minister, and David McGuinty, the public safety minister, shared a two-page explainer, a time-lapse video of the border, as well as other information and data, with Mr. Trump’s border czar, Tom Homan, as part of a campaign to convince Trump allies that Canada was working hard to address the president’s concerns.

The tightening of rules around student visas, and additional border measures, have led to a drop of illegal crossings from Canada to the United States by 89 percent since June, Canadian border data shows, and the ministers shared this information with Mr. Homan on Friday.

The postponement brought relief to several Canadian industries that were facing severe disruptions if the tariffs had come into effect just after midnight Tuesday. But it did not fully remove the uncertainty surrounding them.

“With tariffs on the table, the turmoil and uncertainty persist,” said Candace Laing, president and chief executive at the Canadian Chambers of Commerce. “Tariffs tomorrow instead of tariffs today still leaves businesses, workers, and families in the lurch.”

“This is not a game we want to play when livelihoods depend on existing U.S. relationships,” she added. “We will not sleep easier until tariffs are taken off the table permanently.”

The industry perhaps feeling the most unease is the car-manufacturing sector that is so deeply integrated between the United States and Canada.

“I think it’s a chapter,” said Flavio Volpe the president of the Automotive Parts Manufacturers’ Association, a Canadian trade organization. “But we’re still floating.”

Mr. Volpe said that the fall in U.S. stock prices on Monday because of the tariffs, as well as the emergence of prominent Americans and groups opposed to the measures who are not necessarily allies of Canada should help persuade the Trump administration to permanently abandon the tariffs.

Brian Kingston, the president of the Canadian Vehicle Manufacturers Association, said his members “had been preparing for the worst possible outcome.” he said.

His members, which include Ford, General Motors and Stellantis, he said, now have some “education to do about how integrated this industry is.” Car parts can make multiple trips through factories in Canada, Mexico and the United States before finally ending up in a finished vehicle.

While Mr. Trump agreed to a 30-day suspension of similar tariffs against Mexico, it took two telephone conversations with Mr. Trudeau on Monday to get a last-minute reprieve for Canada.

Pierre Poilievre, the Conservative leader who polls show is likely to win an election this year and become the country’s prime minister, was among many Canadians expressing relief about the tariff suspension.

“But this is not a time to sit back,” he added in a social media post in which he again called on Mr. Trudeau to immediately bring Parliament back to address the trade challenges still facing Canada. It is not scheduled to return until late March to allow the Liberals to elect someone to replace Mr. Trudeau as the party’s leader and prime minister.

Mr. Trudeau announced last month his intention to step down as the party and the country’s leader amid growing dissatisfaction among Canadians over the country’ direction.

The tariffs on Canada and Mexico have been postponed, but a White House official confirms for me that, as of now, an additional 10 percent tariff on goods from China is still set to go into effect at midnight. President Trump said earlier today that he would speak with Xi Jinping within the next 24 hours, but it’s not clear when that call will be held.

Brian Kingston, the president of the Canadian Vehicle Manufacturers Association, expressed relief at the delay of any tariffs. “We had been preparing for the worst possible outcome,” he said. “I hope this results in a permanent decision.”

He said that automakers will continue their “education” efforts about the industry’s continental integration.

Trump confirms in a Truth Social post that he will pause his threat to impose tariffs on Canada for 30 days “to see whether or not a final Economic deal with Canada can be structured.” He said Canada had agreed to new measures to combat the trafficking of fentanyl and illegal migration.

U.S. tariffs on Canada are going to be postponed by 30 days as the two countries negotiate a border deal, Prime Minister Justin Trudeau of Canada said after finishing a second call with President Trump.

“I just had a good call with President Trump,” Trudeau said in a social media post. He said Canada would push ahead with its 1 billion Canadian dollar, or about $680.9 million, border reinforcement plan and deploy additional technology and staff, all of which had been announced previously.

Trudeau said Canada would also appoint a “fentanyl czar” and would: “list cartels as terrorists, ensure 24/7 eyes on the border, launch a Canada-U.S. Joint Strike Force to combat organized crime, fentanyl and money laundering.”

“I have also signed a new intelligence directive on organized crime and fentanyl, and we will be backing it with $200 million,” Trudeau said.

A tariff on energy imported from Canada would almost certainly raise the extremely high cost of electricity in New York, experts on the state’s complex power grid said.

But how much is just a guessing game at this point, they said, because the state’s power supply is so intertwined with Canada’s.

New York imports electricity from Canada, most of it produced by hydroelectric power plants. But Canada also gets some of its power from New York.

“New York as a state imports and exports to Canada on the daily,” said Marguerite Wells, executive director of Alliance for Clean Energy New York. “There are electrons going back and forth all the time.”

On Monday afternoon, Canada was doing the importing, said Daniel A. Zarrilli, former chief climate adviser for New York City. But overnight, the power was flowing the other way across the border, he said.

Not much, if any, of that Canadian power reaches New York City. But the city is tied to the statewide grid, so cost increases ripple from one end to another.

About the only certainty, Mr. Zarrilli said, was that a tariff of 10 percent or more would add costs that would be passed on to consumers to some extent.

“We’re basically putting more cost on the system,” he said. “I have no means of putting a number on it, other than thinking the pass-through costs of the electricity generation are just going to go up.”

In November, the price of residential electricity in New York was about 45 percent higher than the national average, at about 25 cents per kilowatt-hour, according to the U.S. Energy Information Administration.

Ms. Wells, who lives upstate, said she assumed her electric bill would rise at least a little. But she pointed out that the tariff should affect only the cost of the energy she uses, not the price she pays her utility company to deliver it.

Only about one-third of a New Yorker’s electric bill covers the energy used; the rest goes toward delivery and a variety of fees and charges, she said. So, as an example, a 10 percent tariff might add about $3 to a $100 monthly bill, she said.

President Trump said he would place a 25 percent tariff on Canadian imports starting Tuesday, though under an exception the tax would be 10 percent for energy products. There was some confusion on Monday about which tariff level would apply to energy from renewable sources like hydroelectric, wind and solar power.

Not even the agency that oversees the state’s power grid, the New York Independent System Operator, would provide an estimate of the proposed tariff’s impact on consumers. Kevin Lanahan, a spokesman for the system operator, said it was “actively pursuing guidance” on how the electricity market would be affected.

“The U.S. and Canada have one of the most integrated electric grids in the world, allowing system operators in both countries to pool resources for improved reliability and economic efficiency,” he said.

Indeed, Quebec is expected to provide a major new source of renewable power to New York City through a 340-mile transmission line — the Champlain Hudson Power Express — that is being built along the Hudson River. How a tariff would affect that project, currently scheduled for completion next year, was unclear on Monday.

“If there’s a tariff regime in place in a year and a half when that comes on line, there’s a chance that the electricity prices will be higher than people are expecting,” Mr. Zarrilli said.

President Trump’s call with Prime Minister Justin Trudeau of Canada appears to be over given he has now entered the East Room of the White House to celebrate the Florida Panthers, the professional hockey team.

Before taking the Florida Panthers to the Oval Office, Trump told a reporter that his call with Trudeau was “very good.” Asked if he would still impose tariffs on Canada, Trump said, “watch.”

Republicans in Congress are rushing to praise President Trump’s plan to impose tariffs on allies and adversaries alike, even those from agricultural states whose constituents stand to lose the most from a trade war.

The outpouring of praise, peppered only with a few instances of carefully worded skepticism, is another indication that there is unlikely to be any legislative resistance to Mr. Trump’s unilateral move.

On Saturday evening, barely five minutes after Mr. Trump posted about the tariffs he had just signed an executive order for, Representative Glenn Thompson, a Pennsylvania Republican who leads the House Agriculture Committee, praised the decision as an “effective tool” for “ensuring fair trade for American producers.”

“Look no further than Colombia’s about-face on accepting repatriated criminal migrants at the mere threat of tariffs,” said Mr. Thompson of Pennsylvania.

The agriculture panel’s social media feed was replete with Republican praise of Mr. Trump’s tariff plan, an extraordinary outpouring given that the G.O.P. has long been defined by its zeal for free trade.

“Thank you, President Trump! Our country finally has an advocate for American farmers, families, and businesses in the White House!” Representative Randy Feenstra, an Iowa Republican who prides himself on meeting with farmers and families in each of the 36 counties he represents in the state’s northwest corner, wrote in a post on X on Monday.

The message was starkly at odds with the one coming from major groups representing farmers throughout the country, who issued statements warning of dire impacts on the nation’s food producers.

Republican senators were more muted — and some downright silent — in their responses.

Senator Chuck Grassley, another Iowa Republican, on Monday morning pleaded with Mr. Trump on social media to exclude Canadian potash — a key ingredient in fertilizer — from the tariffs. A few hours later, Mr. Grassley cheered what he called the “good news” that Mr. Trump had negotiated a one-month pause on tariffs with Mexico and said he hoped the agreement foreshadowed a resolution with other trading partners.

“Hopefully, negotiating will preempt more talk of tariffs,” Mr. Grassley wrote.

The last time Mr. Trump was in office, he imposed tariffs in 2018 and 2019 on $300 billion of Chinese imports to push China to negotiate a trade deal with the United States. His action triggered a trade war between Washington and Beijing, with China slapping retaliatory tariffs on American products. China also shifted more of its soybean purchases to Brazil and Argentina, a significant blow to U.S. soybean farmers who had long relied on the Chinese market.

That resulted in billions of dollars of lost revenue for American farmers. To help offset the losses, Mr. Trump handed out $23 billion in subsidies from a fund that the Department of Agriculture created to stabilize the farm sector. But that attempt to mitigate the damage was not viewed as a total success. Large farm operations and farmers in the South benefited the most, fueling concerns about fairness and leaving some farmers feeling cheated.

Some Republicans have criticized the tariffs. Senator Rand Paul said bluntly: “Tariffs are simply taxes. Conservatives once united against new taxes. Taxing trade will mean less trade and higher prices.”

And Representative Don Bacon of Nebraska — who represents a leftward-shifting Omaha-based district, making him one of the House’s most vulnerable members — said over the weekend that he was confused about Mr. Trump’s decision to target Canada, arguing that he should focus instead on China and Russia.

Alan Rappeport and Annie Karni contributed reporting.

The United Nations said it was very concerned about the impact of President Trump’s tariffs on the global economy, particularly in developing countries and in places where the population is vulnerable. Stéphane Dujarric, a spokesman for the U.N., said it was “important to note that most global trade continues to follow internationally agreed to rules by the World Trade Organization, which provides stability and certainty for the global economy.”

Also on the call with Democratic senators was Ernie Tedeschi, the director of Yale University’s nonpartisan Budget Lab. He said a recent study from his team calculated that the average American family would likely lose close to $1,250 in disposable income per year if Trump’s original tariff plan was enacted and triggered retaliatory tariffs. That number falls to just under $700 a year without the tariffs on Mexico, he said, adding that the middle class bears the largest financial burden.

“Tariffs are not an equitable tax. They pinch the middle class more than they pinch upper-income households,” Tedeschi said.

President Trump is brandishing the U.S. economy like a weapon, threatening to put more than a trillion dollars of trade on the line with economic wars on multiple fronts.

In a high-stakes confrontation that lasted over the weekend and into Monday, Mr. Trump promised to put tariffs on the United States’ closest trading partners, which are together responsible for more than 40 percent of American imports, to try to force them to accede to his demands.

Mr. Trump was pushing Canada, Mexico and China to stop flows of migrants at the border — one of his major domestic policy issues — as well as to stem shipments of deadly drugs, and offer the United States better terms when it comes to trade relationships.

Both Canada and Mexico earned slight reprieves on Monday after Mr. Trump agreed to delay tariffs of 25 percent — which were supposed to go into effect on Tuesday — for a month. That decision came after President Claudia Sheinbaum of Mexico promised to reinforce the U.S.-Mexico border with 10,000 members of its National Guard. Justin Trudeau, the Canadian prime minister, said Canada would appoint a fentanyl czar, launch a joint strike force to combat organized crime and list cartels as terrorists, among other steps.

China has not received any such reprieve and Mr. Trump on Monday said that the 10 percent tariffs that will go into effect on Tuesday were simply an “opening salvo.”

Speaking from the Oval Office, the president also made clear that he would use tariffs liberally to get other governments to give him what he wants, essentially saying he would leverage America’s economic strength to bully other nations.

“I don’t want to use names, but tariffs are very powerful, both economically and in getting everything else you want,” Mr. Trump said during remarks in the Oval Office. “When you’re the pot of gold, the tariffs are very good, they’re very powerful and they’re going to make our country very rich again.”

The president is right that the American economy is a powerful weapon, and that tariffs, if he chose to put them into effect, would hit other countries harder. Canada and Mexico in particular are deeply dependent on trade with the United States. They send more than 80 percent of their exports to the United States, and could be crippled by a prolonged fight.

But many economists say the strategy would cost the United States, too. They estimate that as strong as the American economy is, trade wars would weaken it by raising prices, stalling investment, slowing growth and dragging down exports. Many farmers and businesses who would see their costs go up and export markets evaporate have protested the risk.

It remains to be seen what the president will do once his 30 day timeline ends. But even if the president ultimately does not follow through this time around, the uncertainty his policies have created could discourage businesses from investing in new factories and hiring workers until they have a clearer picture of how trade will unfold.

Emily Blanchard, an economics professor at Dartmouth’s Tuck School of Business, argued that tariff threats eat away at U.S. economic leverage. She said that Mr. Trump was “undermining the trust that provides the foundation of U.S. strength” by throwing around the country’s weight in global markets.

If companies and investors expect the United States to deploy tariffs regularly, they will hedge against future disruptions by reducing their reliance on American markets, she said. “Trade policy is an economic weapon that becomes less powerful every time it is used,” she said.

The president has briefly acknowledged that trade wars could hurt Americans, but he has argued that they will hurt other countries more.

“WILL THERE BE SOME PAIN?” he wrote on social media on Sunday. “YES, MAYBE (AND MAYBE NOT!). BUT WE WILL MAKE AMERICA GREAT AGAIN, AND IT WILL ALL BE WORTH THE PRICE THAT MUST BE PAID.”

A news release accompanying Mr. Trump’s trade executive orders over the weekend stated that access to the American market was a “privilege” for foreign governments. The White House noted that trade accounted for 73 percent of Mexico’s economic activity, 67 percent of Canada’s and 37 percent of China’s. But trade is only 24 percent of U.S. gross domestic product, it said.

Wendy Cutler, a former U.S. trade negotiator and vice president at the Asia Society, said Mr. Trump was correct that trade wars would be more painful for Canada and Mexico. “There is no doubt that our partners will be more severely impacted than the United States, with over three-fourths of their exports destined for our market,” she said.

“Still, U.S. consumers, companies and economy will also feel the pain, particularly when subject to retaliatory actions by our partners.”

Researchers at the Peterson Institute for International Economics in Washington have estimated that a 25 percent tariff on Canada and Mexico and a 10 percent tariff on China would hit other countries the hardest, but would also slow the U.S. economy.

Canadian and Mexican gross domestic product would both shrink by a full percentage point by 2027, they estimate. G.D.P. in the United States would fall by only about a third of that. While that may not seem like much, there are few actions that American presidents have willingly taken that cut economic growth by so much.

Tariffs on Canada and Mexico would be particularly painful because, after 30 years under a common trade agreement, many companies have set up supply chains that cross North American borders. Companies making petroleum, cars, consumer care products, tequila, steel and other products have expressed concern over the tariffs.

Ontario, the province that is home to Canada’s auto industry, estimated that 450,000 jobs were at risk because of the tariffs. Officials there announced that they would offer tax deferrals and other measures to help businesses affected by the tariffs.

Beyond the effects on companies, trade experts said the aggressive threats could be longer-term damage to U.S. interests. That is because the tariff threats would eat away at international confidence that the United States will abide by trade rules and norms that govern when governments deploy tariffs and why.

Edward Alden, a trade expert at the Council on Foreign Relations, said that the United States had nurtured a system of international rules and predictability for decades. With Mr. Trump threatening to deploy tariffs in a “random, incomprehensible fashion, he said, “that era has come to an end.”

“The United States is now signaling that tariffs are an all-purpose club to be used for whatever policy goal the president wishes,” he said. “That formula will create enormous, in many ways unprecedented, uncertainty not just in North America but in the entire global economy.”

Canada and Mexico had been poised to retaliate if the tariffs went into effect, despite a U.S. threat to escalate tariffs further if they do. Canada announced on Sunday that it would target American-made honey, tomatoes, whiskey and refrigerators. Before the one-month reprieve, Mexico’s president had also said her country would respond.

Foreign officials have been frustrated that Mr. Trump’s metrics for having tariffs removed were subjective and vague. He had expanded his goals in recent days, saying that countries would also need to reduce their trade surpluses with the United States, in addition to action on drugs and migrants.

Asked on Monday what Mr. Trudeau could offer the United States in order to forestall tariffs, Mr. Trump answered: “I don’t know. We have big deficits with Canada, like we do with all countries.”

Some have implied that Mr. Trump’s real goal is to shift the blame for domestic problems to foreign countries.

Ms. Sheinbaum said in a social media post on Saturday that if the United States really wanted to address drug issues, it should look to internal measures. It could combat fentanyl sales on its streets, address money laundering or start a campaign to prevent drug consumption, she wrote.

Others have contended that Mr. Trump’s motives may be more about sending political signals to his supporters, rather than really affecting drugs, migrants or trade.

Heather Hurlburt, a former Biden administration trade official, said at an event at the Council on Foreign Relations in January that “signaling in politics” was the “single most important purpose of tariffs.”

“This is a signaling game,” she said.

Economic research published last year found that Mr. Trump’s tariffs in his first term had not accomplished his stated aims of increasing manufacturing jobs, but that they had still benefited the president politically, by winning over voters for the Republican Party.

Ms. Hurlburt said that after Mr. Trump’s first term, it was “duly noted across the political spectrum” that tariffs had been incredibly effective in getting people to pay attention.

“If you want to signal to the public that you are taking on issue X, Y or Z, tariffs are now an irresistible way to do it,” she said.

The call between Prime Minister Justin Trudeau of Canada and President Trump call is in progress, a Canadian government official says.

President Trump has twice today — on Truth Social and in remarks from the Oval Office — brought up a fairly niche trade topic that was on nobody’s 2025 regulatory bingo card: The inability of U.S. banks to operate fully in Canada.

He’s right. Canada’s tightly regulated financial sector is dominated by six domestic banks, and foreign lenders are largely blocked from competing in areas like mortgages. The mystery is why this suddenly bothers Trump; it isn’t a topic that bubbles up much for top executives at major U.S. banks, who have shown no interest in expanding into Canada.

On a call with Democratic senators this afternoon, Senator Chuck Schumer, the minority leader, condemned the Trump tariffs as an attack on Americans’ wallets.

“These nonsense tariffs equate to a tax increase on the American people,” Schumer said. “And the president’s advice is, ‘live with it and be OK with some pain,’” he added.

Europe, you’re next.

That’s the latest message from President Trump, who has repeatedly said in recent days that he would slap punitive tariffs on the 27 members of the European Union.

Tariffs “will definitely happen with the European Union,” Mr. Trump told the BBC Sunday evening, and they are coming “pretty soon.” He doubled down on the threat on Monday, complaining about deficits in auto and farm products. New tariffs were set to go into effect on imports from Canada, China and Mexico on Tuesday, but on Monday Mexico and Canada were granted a one-month delay.

“The European Union has abused the United States for years, and they can’t do that,” Mr. Trump said on Monday.

A head-spinning blitz of executive orders and policy reversals related to international trade, aid and agreements has come out of the White House in the past two weeks. But one common thread is that Mr. Trump has directed the harshest penalties at some of America’s closest economic and military allies.

One reason is that the United States has large trade deficits with Mexico, Canada and the European Union in addition to China, said Agathe Demarais, a senior policy fellow at the European Council on Foreign Relations.

“Trump is obsessed with trade deficits,” she said. And he may be “starting with the places where he feels he will have quick wins.”

Of course, trade surpluses are not necessarily any indication of a country’s economic health. The last time the United States had an overall trade surplus was 1975, when the American economy was still in a severe recession.

The United States did have a trade surplus in 2023 with Britain, according to the U.S. Bureau of Economic Analysis. And that may help Britain avoid tariffs. “I think that one can be worked out,” Mr. Trump said, contrasting Britain with Europe.

As for the European Union, Mr. Trump has characterized the bloc’s trade practices as an “atrocity.” But tariffs imposed by the United States and the European Union on each other are pretty similar.

“The pattern of protectionism between the U.S. and Europe is very even, and there is absolutely no evidence that the U.S. has been taken advantage of,” said Kimberly Clausing, an economist at the Peterson Institute for International Economics in Washington. “This claim is disingenuous.”

Products exported from the United States to the European Union are on average subject to a 3.95 percent tariff, according to ING Global Markets Research. A 3.5 percent tariff on average is added to products from the European Union that head west across the Atlantic.

The disparities, however, are bigger on some items, like cars. The European Union tariff is 10 percent, compared with 2.5 percent from the United States. And E.U. tariffs on food and beverages are on average 3.5 percent higher than those set by the United States. Mr. Trump has long complained about both sectors.

The United States is the No. 1 buyer of E.U. exports, accounting for nearly 20 percent of the total in 2023, according to Eurostat. The bloc’s surplus on goods was roughly $160 billion; there was a $107 billion deficit on services.

Mette Frederiksen, Denmark’s prime minister, said Monday that she would “never support fighting allies,” but that “if the U.S. puts tough tariffs on Europe, we need a collective and robust response.”

Donald Tusk, Poland’s prime minister, said, “We have to do everything to avoid it — totally unnecessary and stupid tariff war or trade wars.”

For months, European leaders have quietly been preparing for how to respond. Business leaders and trade associations are warning that the brewing trade war and the unpredictable way in which it is being waged could slow investment. American tariffs on European goods would also hurt companies when they were weakened by flagging demand at home and in China.

The U.S. Chamber of Commerce to the European Union issued a statement on Monday criticizing potential tariffs, arguing that they would invite retaliation and cause companies on both sides of the Atlantic to suffer.

German business leaders were reluctant on Monday to comment on the possibility of tariffs on Europe, but they reacted with a mixture of concern and resignation to those targeting Mexico and Canada.

“German industry is directly affected by the tariffs, as it also supplies the U.S. market from plants in Mexico and Canada,” said Wolfgang Niedermark, a board member of BDI, a German industry lobby group. “The automotive industry and its suppliers, including the chemical industry as a supplier of chemical raw materials, will be hit much harder than other sectors.”

Many of the 2,100 German companies that have operations in Mexico, including BMW, Volkswagen and Audi, chose to build there after Mr. Trump signed a trade agreement with Mexico and Canada during his first term, when the threat of tariffs against Germany loomed.

Nearly a quarter of the 1.3 million vehicles that German automakers sold in the United States last year were produced in Mexico. In addition to the car companies, a web of auto parts suppliers, such as Bosch and ZF, have research and production plants there.

Asian and European stock markets fell on Monday, with some of the biggest drops in share prices among auto manufacturers.

Economists at the Prognos Institute in Switzerland calculated that 1.2 million jobs in Germany were dependent on exports to the United States, and that as many as 300,000 of them could be endangered if tariffs against Europe came into effect.

Europe’s luxury industry has also been bracing for a hit. In 2019, the United States briefly imposed 25 percent tariffs on French wines and Italian cheeses, as well as luxury leather handbags and luggage from brands like Louis Vuitton and Gucci.

Bernard Arnault, the head of the LVMH Moët Hennessy Louis Vuitton empire, has sought to cultivate direct ties with Mr. Trump, who personally invited him to attend last month’s inauguration in Washington. At an earnings presentation last week, Mr. Arnault said that by lowering the corporate tax to 15 percent and “welcoming you with open arms,” Mr. Trump was making the United States more attractive for companies.

There can be reasons for a country to worry about too large a trade deficit, said Ms. Clausing, the Peterson Institute economist. But the United States is not facing those problems at the moment.

The trade deficit signals that American consumers are getting a lot of stuff from the rest of the world, she explained. If tariffs drive up prices and Americans have to pay more, as most economists expect, their standard of living will go down.

Liz Alderman contributed reporting from Paris, Melissa Eddy from Berlin and Jeanna Smialek from Brussels.

Ontario, the province that is home to Canada’s auto industry, plans to offer financial aid to businesses affected by the impending tariffs. Peter Bethlenfalvy, Ontario’s finance minister, announced that the province would be deferring taxes of up to 10 billion Canadian dollars, or $6.87 billion, and offering other measures, including payroll tax relief to help employers avoid layoffs. The province estimates that 450,000 jobs would be at risk if the tariffs take effect.

A top official at the Federal Reserve warned that businesses were planning to pass the increased costs from tariffs onto customers.

Raphael Bostic, president of the Federal Reserve Bank of Atlanta, said leaders at companies he speaks to said they would pass higher costs through “100 percent.” Whether that was a sustainable strategy would depend on whether consumers “rebel.” He made clear that uncertainty about the economic outlook had risen dramatically in recent weeks.

“I had uncertainty on December 31. The amount of uncertainty that we have today is greater than that,” Bostic said at an event in Atlanta. He is among officials to urge a cautious approach to further rate cuts after the Fed pressed pause last week.

China’s ambassador to the United Nations, Fu Cong, said on Monday that China was filing a complaint with the World Trade Organization over President Trump’s tariffs and would consider retaliatory action. “We are firmly opposed to this unwarranted increase,” he said. “We do believe this is in violation of W.T.O. rules. That’s why China is filing a complaint at W.T.O., and we may be forced to take countermeasures. There is no winner in a trade war.”

The U.S. auto industry dodged a supply chain catastrophe after President Trump delayed tariffs on products from Mexico and Canada for at least a month on Monday. The tariffs most likely would have raised car prices by thousands of dollars, analysts said.

But automakers must still reckon with the prospect of severe disruptions as Mr. Trump continues to brandish tariffs against two countries that play an essential role in the U.S. car market.

The deals with Mexico and Canada were reached after the auto industry warned that prices would increase almost immediately if the United States imposed tariffs, forcing carmakers to cut jobs in reaction to plunging sales.

Mexico produces billions of dollars’ worth of automotive components and vehicles like the Chevrolet Equinox and Blazer and the Ford Mustang Mach-E electric car and Maverick pickup.

Factories in Ontario produce several of the most popular cars sold in the United States, including versions of the Chevrolet Silverado pickup, the Honda CR-V and Toyota’s RAV4. Canada is also a major supplier of engines and transmissions.

“The trade in cars and car components is too important to both sides,” said Erik Gordon, a professor at Ross School of Business at the University of Michigan.

Investors registered relief after Mr. Trump confirmed that he would not immediately impose 25 percent tariffs on vehicles and other products from Mexico and Canada.

Shares of General Motors, which produces about one-third of its cars and trucks for the North American market in Mexico and was seen as the most vulnerable to tariffs, recouped some of their losses, closing down about 3 percent. Earlier in the day, they were down nearly 10 percent.

Brian Kingston, the president of the Canadian Vehicle Manufacturers’ Association, expressed relief at the delay of any tariffs. “We had been preparing for the worst possible outcome,” he said. “I hope this results in a permanent decision.”

Still, in an industry that has to plan years in advance, even the specter of trade conflicts creates an environment of extraordinary uncertainty. Automakers are likely to prepare for more turmoil by stockpiling cars and parts, and by trying to increase exports from Canadian or Mexican factories to other countries. But they would not be able to quickly move assembly lines to the United States.

Michael Lohscheller, the chief executive of Polestar, which manufactures electric vehicles at a factory in South Carolina owned by its sister company Volvo Cars, said carmakers needed to develop business plans that were immune to politics.

“The industry always had topics like this,” Mr. Lohscheller said in an interview on Monday. “It’s something we have to work through.” Polestar and Volvo are both majority-owned by Zhejiang Geely Holding Group of China.

Tariffs could force carmakers to raise prices by thousands of dollars and eventually lead to plant closures and job losses if sales plunge as a result of higher prices. Tariffs would have also had a trickle-down effect on the used car market, said Jenni Newman, editor in chief of Cars.com, an online car-shopping site.

“Likely used cars prices will go up, too,” she said.

Representatives for G.M., Ford, Stellantis, Honda and Toyota declined to comment on Monday.

BMW, which has large factories in San Luis Potosí, Mexico, and Spartanburg, S.C., declined to comment specifically on the latest action by the White House, but said in a statement that tariffs “hinder free trade, slow down innovation and set a negative spiral in motion.”

Ian Austen contributed reporting.

“I’d like to see Canada become our 51st state,” President Trump said from the Oval Office. Asked if there was anything Prime Minister Justin Trudeau could offer to avoid tariffs, Trump said he didn’t know. “We have big deficits with Canada like we do with all countries.”

Trump also told reporters in the Oval Office that he expected to speak with Xi Jinping of China in the next 24 hours. He said his tariffs of 10 percent against China were just “an opening salvo.”

President Trump, speaking from the Oval Office, repeated a litany of complaints he has about Canada, just over an hour before his scheduled call with Prime Minister Justin Trudeau.

“We aren’t treated well by Canada,” he said, adding that he told Trudeau on a morning call that American banks are excluded from Canada. Trump also repeated that the United States did not need Canada to make cars, and didn’t need Canadian lumber or agricultural products.

President Trump told reporters in the Oval Office that he had “a great talk with Mexico” this morning and that Mexico’s deployment of 10,000 troops to the southern border to beef up illegal migration and drug enforcement would be permanent. Trump said tariffs were not totally off the table. The White House delayed the economic penalty by a month.

Trump said he expects another “good conversation” with Prime Minister Justin Trudeau of Canada this afternoon. They have a call scheduled for 3 p.m. Eastern time. The 25 percent tariffs against Canada are still scheduled to take effect on Tuesday.

Leave the Cheetos, Old El Paso taco kits, Charmin toilet paper and Jack Daniel’s whiskey on the shelves. Do Canada proud and shun American products in favor of those made in Canada. The times call for it.

These are the messages being promoted on videos that have flooded social media in Canada seeking to explain how to shop strategically during a coming trade war.

With 25 percent tariffs on Canadian exports scheduled to begin on Tuesday, Canada announced retaliatory tariffs on 155 billion Canadian dollars ($106 billion) worth of U.S. goods, igniting emotional appeals from political leaders across the country to buy locally made products.

“Now is the time to choose products made right here in Canada,” Prime Minister Justin Trudeau said in a post on X. “Check the labels. Let’s do our part. Wherever we can, choose Canada.”

Grocery stores have rapidly emerged as a frontline, with the Canadian sketch comedy show “This Hour Has 22 Minutes” taking a crack at the subject in a recent viral segment starring two of the show’s cast members, Mark Critch and Chris Wilson, shopping at a grocery store.

“We’re in a trade war, you traitor,” Mr. Critch said, plucking American-made items out of Mr. Wilson’s cart and suggesting Canadian-made alternatives, like Hawkins Cheezies puffs and Kraft Dinner macaroni. (The punchline of the sketch is an inside joke among Canadians, whose resentment toward the country’s largest food retailer, Loblaws, has deepened amid high grocery prices.)

On social media, videos appealing to Canadian patriotism — some set to dramaticmusic — are providing guidelines for how to shop for snacks and produce to support local industries and businesses.

Canada’s opposition leader, Pierre Poilievre of the Conservative Party, called for the country to deploy 2,000 troops to its border with the United States and make major technology investments to improve surveillance there, as part of negotiations with the United States to gain a reprieve from President Trump’s tariffs. Mexico got tariffs postponed by a month by offering border measures. Trump and Prime Minister Justin Trudeau of Canada are scheduled to speak at 3 p.m. Eastern time. A morning phone call between the two ended without a deal.

How the U.S. economy will be impacted by tariffs is not yet clear. So, too, is the Federal Reserve’s response in an environment of high inflation, suggesting officials will keep further interest rate cuts on hold until they gain additional clarity on the outlook.

Susan Collins, president of the Federal Reserve Bank of Boston, endorsed that view on Monday, saying that there was no urgency to make additional policy decisions at this time.

“It’s really appropriate for policy to be patient, careful, and there’s no urgency for making additional adjustments, especially given all of the uncertainty,” said Ms. Collins in an interview with CNBC.

Much will depend on how long the tariffs are in place and whether President Trump decides to escalate trade tensions once again and impose them much more broadly.

Already, the administration has reached a deal with Mexico to delay the imposition of tariffs, suggesting the final economic impact could be more muted than expected if these measures turn out to be in place only temporarily.

At least directionally, the expectation is that an escalation in trade tensions would cause prices for some goods to rise and lower growth over time. The fear is that higher prices would sap business activity, as companies pulled back investments and retrenched in the face of higher uncertainty. If some of the higher costs are passed onto consumers, Americans would either have to redirect their purchases or cut back on other spending.

What happens with households’ and businesses’ expectations about future inflation is key to how the Fed will react. Ms. Collins stressed that if those expectations stayed in check, as in Americans did not come to assume that prices were poised to rise, the Fed could look through or not react to that outcome.

With the economy on stable footing, the Fed has much more flexibility to move carefully with further rate cuts than it otherwise would if the labor market was weakening.

Canada found itself in a precarious position on Monday morning after Mexico cut a deal with President Trump to postpone tariffs in exchange for a major deployment of forces along the border between the two countries.

Prime Minister Justin Trudeau of Canada spoke to President Trump on Monday morning but no such compromise was reached between the two. A senior Canadian government official with knowledge of the call said the situation was still in flux ahead of a second phone call between the two leaders scheduled for 3 p.m. Eastern, but did not express optimism that a compromise could be reached.

The diverging fates of Mexico and Canada highlight an early rift between the two allies who, together with the United States, have long had a deep tripartite free trade agreement, originally known as NAFTA. Its successor, known as the US-Mexico-Canada agreement, was negotiated by Mr. Trump during his first presidency.

But when Mr. Trump first threatened tariffs against Canada and Mexico in November, citing illegal migration and fentanyl flowing into the United States from both neighbors, some Canadian politicians rushed to throw Mexico under the bus.

Ontario’s premier, Doug Ford, a prominent voice on the topic, and others suggested that the United States should form a separate deal with Canada and ditch Mexico. The argument focused on the vast difference between the two borders: Only a fraction of the undocumented migrants and fentanyl entering the United States come from Canada compared to Mexico.

While Mr. Trudeau did not suggest ditching Mexico, the relationship between the two countries suffered deeply. The senior Canadian official previously said that the trust between them had been reduced to zero.