Two of Chicago's largest service-worker unions broke publicly with Mayor Brandon Johnson on Tuesday, endorsing Illinois Secretary of State Alexi Giannoulias for mayor and delivering a major blow to Johnson's bid for a second term. SEIU Local 73 and Local 1, which together represent about 50,000 Chicago workers in schools, parks, airports and office buildings, announced their decision after an endorsement vote Monday, formalizing a rift with the Chicago Teachers Union that had been building since early 2025.

SEIU Locals 1 and 73 Endorse Giannoulias, Shattering Progressive Coalition

The endorsement rally at Local 1's downtown headquarters Tuesday morning made official what political insiders had observed for years: Johnson's second-biggest labor ally from 2023 has left his tent. "Chicago's working families aren't better off than they were four years ago," Local 1 President Genie Kastrup declared, adding, "We need a mayor who understands that being pro-worker is more than a campaign promise. It's about protecting good union jobs."

Local 73 President Dian Palmer led the room in chants of "Union strong, Chicago proud, Alexi for mayor say it loud." The stakes are considerable: SEIU affiliates contributed more than $4.5 million to Johnson's 2023 campaign and supplied scores of campaign workers and materials. Those resources will now presumably flow to Giannoulias, who reported a campaign war chest of $19.2 million, while Johnson reported $379,471 in cash on hand. Notably, SEIU Healthcare did not join the two locals, keeping the SEIU Illinois State Council out of the race for now.

The Unraveling of a 2023 Alliance

Four years ago, a coalition of labor unions including the Chicago Teachers Union and SEIU came together to endorse a Cook County commissioner and former CTU organizer named Brandon Johnson for mayor. That coalition propelled Johnson to the fifth floor of City Hall in 2023. SEIU Healthcare and Local 73 endorsed him before the first round of voting that year, with Local 1 backing him during the runoff against former CPS CEO Paul Vallas.

The alliance began publicly fraying in early 2025, according to the Sun-Times' account of the long-simmering feud. Progressive Ald. Jeanette Taylor noted this July that there lacks "balance" in how the two unions' memberships have fared. Asked this summer about the prospect of a CTU and SEIU breakup under his watch, Johnson had one answer: "I'm running the city of Chicago. I'm not running labor."