Of the 15 largest cities, only Chicago lets its mayor fill vacancies on the city council. Mayor Brandon Johnson is about to exercise that long Chicago tradition by filling a vacancy he created.

Chicago Mayor Brandon Johnson will soon crown his first City Council member to fill a vacancy the mayor created.

On Feb. 28, Johnson named his top ally in the City Council, 35th Ward Ald. Carlos Ramirez-Rosa, to the top post in the Chicago Park District. This appointment gives the mayor the privilege of selecting Ramirez-Rosa’s successor – enabling him to participate in a long tradition of Chicago mayors filling City Council vacancies.

But while this is undeniably a Chicago tradition, Chicago is the only big city in the nation that operates this way.

Like any legislative body, Chicago’s City Council is meant to act as an independent check on the executive – in this case the mayor.

But the Chicago mayor’s unique power to directly appoint aldermen greatly undermines the council’s independence.

For over 100 years, Chicago has operated with a 50-member city council, with each of the 50 wards electing a single alderman.

Council members largely act independently of one another, behaving as what some have termed “ mini-mayors .” They focus on matters pertaining to their own wards instead of keeping the city as a whole in view. In fact, fewer than 10% of the over 75,000 proposed City Council ordinances from 2011 to 2018 addressed citywide issues (i.e., city budgets, taxes, contracts or citywide laws), and most of those were put forward by then-Mayor Rahm Emanuel, according to an analysis by the Better Government Association.

If a vacancy occurs among the “mini-mayors,” the mayor, who serves as the city’s executive authority, appoints a successor.

Chicago is the only major city among the 15 largest to fill City Council vacancies through mayoral appointment.

Special elections are the most common method for filling city council vacancies in the 15 most heavily populated U.S. cities. In the big cities without special elections, vacancies are filled by council appointment.

Chicago’s unique status in empowering the mayor to fill vacancies is likely because Chicago is the only big city in which this process is governed by state law . In every other major city, the process is laid out in a city charter .

Not only is Chicago’s governance structure unique in giving the mayor the power of appointment to fill city council vacancies, but the power to appoint city council vacancies in itself carries unique weight in Chicago – regardless of who appoints.

First, council members enjoy a significant incumbency advantage because of low turnout in municipal elections. Overall, municipal election turnout is 40% lower than participation in November elections in Chicago, with several wards seeing an average drop-off of more than 50%. The election schedule may have something to do with this: Chicago is the only big city in the country to hold its municipal elections in February of odd years.

Second, Chicago is the only city among the top 10 by population without mayoral or council term limits.

Finally, the appointment process undermines democracy by circumventing elections.

Chicago City Council members can campaign for reelection by telling constituents they’re running to represent them, win the election, then quickly negotiate their resignation with the mayor.

Less than a year after his re-election in 2015, Ald. Will Burns resigned to become the director of Midwest policy for Airbnb. An appointed successor, rather than an elected official, served out the last three years of his four-year term.

Today in Chicago, when a vacancy arises, the mayor holds all the cards.

So how can this change?

For starters, Johnson’s historically low approval rating could embolden the City Council to reject his pick for Ramirez-Rosa’s successor. That would be a welcomed show of independence from the council and it would discourage other Johnson allies from horse-trading on their own replacements.

Absent that show of independence or the adoption of a city charter , that leaves state law.

Illinois state lawmakers should introduce and pass a bill ending Chicago’s mayoral prerogative for filling city council vacancies, putting it in line with every other big city in the country.

This structural change should be pursued not as a personal axe to grind with Johnson – though there are many lawmakers who would prefer new leadership in City Hall.

Rather, it is a chance to better design city government to provide healthy checks and balances.

That’s a major benefit to Chicago democracy – no matter who is mayor.