The International Association of Fire Fighters announced on Thursday that it would not be endorsing a candidate for president this year.
The news is a particular blow to Vice President Kamala Harris, since the union was the first to endorse Joe Biden's presidential bid in 2020.
In a statement, Edward A. Kelly, the union's president, said that the group's executive board voted on Thursday by 1.2% not to endorse.
He added that the board "determined that we are better able to advocate for our members and make progress on the issues that matter to them if we, as a union, are standing shoulder-to-shoulder. This decision, which we took very seriously, is the best way to preserve and strengthen our unity."
The union represents over 350,000 firefighters, emergency medical workers and rescue workers throughout the U.S. and Canada.
Both presidential campaigns made personal appeals to the union’s members at a convention in Boston in August, with Minnesota Gov. Tim Walz and Sen. JD Vance of Ohio speaking at the event.
Harris also addressed union members during a separate IAFF legislative conference in Washington, D.C., in March, before Biden dropped out of the race.
Although the union came out quickly in backing Biden in 2020, four years earlier, the IAFF also chose not to get involved in the presidential race.
In 2019, Trump, then president, blasted the union's leadership, writing in a tweet: "The Dues Sucking firefighters leadership will always support Democrats, even though the membership wants me. Some things never change!"
In another tweet the same day, he touted the support union members, writing, "I’ll never get the support of Dues Crazy union leadership, those people who rip-off their membership with ridiculously high dues, medical and other expenses while being paid a fortune. But the members love Trump. They look at our record economy, tax & reg cuts, military etc. WIN!"
The Harris campaign did not immediately respond to a request for comment Thursday.
In a campaign email, the Trump camp called it "another crushing blow to Kamala" and said the International Association of Fire Fighters is "the second high profile union to snub [Harris'] campaign in recent weeks following the Teamsters non-endorsement last month."
In September, the Teamsters union, which represents over 1 million truck drivers, freight workers and others, also declined to endorse a presidential candidate. But a survey of rank-and-file members made public by the group’s leadership showed that 60% of rank-and-file union members preferred to endorse Trump over Harris. Just 34% of members backed Harris.
The AFL-CIO and the United Auto Workers union — which represent millions of workers combined — have each endorsed Harris this cycle.
During his remarks to the union's members in August, Walz spoke about the importance of unions and how he is proud to be a “card-carrying” member of his state teachers union.
Walz said that when he and Harris are in office, they will “make sure you have all the resources and protections you need to do your jobs and your service is respected and that you come home safe every night.” He added that, if elected, Harris will sign the PRO Act, which would make it easier for unions to organize.
The next day, Vance, Trump's running mate, spoke at the convention and was met with several boos when he took the stage.
“This may come as a shock to you, but once upon a time I wasn’t a Trump guy either,” Vance said, noting that a firefighter friend named Matt from Dayton, Ohio, was ultimately one of the bigger influences in helping him come around on Trump.
“I changed my mind because he did a good job for the American people," Vance told the crowd.
