There are not many cities in the world where the local government puts on a house-music festival. There are even fewer where it would be as delightful as the one held in Chicago over the first weekend of June. On a sunny Sunday afternoon people of all races and all ages filed into Millennium Park downtown, many clutching blankets, coolers and folding camp chairs. One attendee, however, was clearly not welcome. Around sunset the headliner, Farley “Jackmaster” Funk, a storied Chicago DJ, invited on a special guest. As Brandon Johnson, the mayor, jogged onto the stage, a deafening chorus of boos rang out. Within 45 seconds he had left again, his seemingly truncated message that Chicago is “the greatest frickin’ city in the world” not enough to silence the din of dissent.

Booing politicians is a long-established tradition in the Windy City (savvier ones know the best moment to appear is early, before the crowd starts drinking). Yet Mr Johnson, who won a surprising election victory last year with the support of Chicago’s teachers’ union, is already unusually unpopular. According to a poll conducted in late April, a year after his election, just 9% of Chicago residents consider him to be doing an “above average” job; a majority say his work is below average. Even among non-white voters—his base—below-average ratings outnumber above-average ones four to one.