The International Association of Fire Fighters was the first union to back Joe Biden in 2020 — effectively doing so even before he entered the crowded Democratic primary. But nearly eight months after the president launched his re-election bid, the organization remains on the sidelines and faces internal divisions about whether to endorse at all in 2024.

Biden has prided himself on a connection with firefighters for his whole political career, and he and his team have continued to cultivate relationships with the union’s leaders since taking office. Those same leaders, though, are mindful that not all of the 343,000 firefighters and paramedics who belong to the union agreed with the 2020 endorsement, and so they are taking a more deliberate approach to 2024, according to two sources familiar with the deliberations.

The situation illustrates how Biden, who has described himself as the most pro-labor president in American history, still faces a challenge in securing the votes of rank-and-file union members, even if many prominent national labor organizations have thrown their support behind him.

Former President Donald Trump has pulled away working-class voters, including some who have traditionally been Democratic voters like union members.

“Biden and his administration has been good to firefighters,” said Mike Bresnan, the leader of the Philadelphia affiliate of the IAFF, adding that it still might not be enough to earn his or other members’ votes.

“There are other issues that affect our membership,” he said, mentioning support for the Second Amendment among them.

The divide within the firefighters union was on display Monday when Biden traveled to Philadelphia for an event at a local firehouse to highlight one of the IAFF’s top legislative priorities — renewing and increasing funding for what’s known after the SAFER Grant program, which provides federal dollars to hire first responders.

Speaking before Biden at what was an official event, not a campaign event, IAFF General President Edward Kelly noted that the president had championed the grant program as a senator.

“Properly staffing and equipping fire departments keeps our communities safe and saves the lives of civilians and firefighters, alike. Nobody knows this better than Joe Biden,” Kelly said.

On hand, too, was the former IAFF official Biden had appointed to lead the U.S. Fire Administration, Lori Moore-Merrell. Biden’s chief political lieutenant, Steve Ricchetti, made what was for him a rare day trip with the president to attend as well.

Watching, but not participating in the event, was Bresnan. In September 2020, Bresnan had issued a statement pledging IAFF Local 22’s support for Trump and attacking the national union over its “undemocratic” endorsement process. Trump’s campaign touted the news and planned to hold an event with Bresnan and other firefighters in Philadelphia the following week — but the trip was canceled when Trump contracted Covid-19.

Biden referred to Bresnan during his remarks Monday, detailing a call he placed to the local union leader after a row house fire in Philadelphia in 2022 that led to 12 deaths, including those of nine children. Bresnan had told the president about how multiple Philadelphia fire stations were shuttered after the 2008 recession, and that if one close to the site of the fire had remained open, they might have saved more lives. Biden told him he would look into the issue.

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On Monday, Biden came with a check — a $22.4 million SAFER grant that the White House said would allow the city to fund 72 firefighters’ salary and benefits for three years, while reopening three firehouses — including the one he visited, which would have been closest to the 2022 fire.

“You can cash it at a local bank,” he joked. “Mike, I kept my promise and got the job done.”

In an interview, Bresnan said that despite Biden mentioning him and their past phone call on Monday, he didn’t have a chance to meet with Biden personally at the event. He said he had been told at one point before the event he would be part of the speaking program, but ultimately only watched it from the rear of the firehouse.

He did, however, speak with Kelly about whether the national union would decide about its 2024 endorsement, and how it would do so. He encouraged Kelly to make sure they surveyed its membership as part of the process, and that he expected they’d find there are pockets of support for Trump.

Even before the IAFF endorsed Biden in 2020 — timed to coincide with his official launch in April 2019 — it hosted something of an early pep rally a month earlier, handing out signs reading “Run Joe Run” before Biden addressed their 2019 legislative conference in Washington.

Support from the union was a key talking point for Biden’s 2020 campaign argument about his electability — especially after it had declined to endorse Hillary Clinton in 2016, a signal of her weakness among working-class, white, male voters that helped tip the balance for Trump.

A spokesperson for the IAFF declined to comment on its endorsement process for 2024. Kelly took over as general president of the IAFF in 2021, succeeding Harold Schaitberger, a longtime friend of Biden’s who served in the role for two decades.

Biden officials said the event on Monday was not indicative of any stepped-up effort to secure the IAFF’s endorsement — but simply the latest example of the president’s long-standing commitment to, and personal connection with, firefighters.

“President Biden was proud to travel to Philadelphia on Monday to announce millions of dollars in support for these heroes. Just as he’s proud to have spent his career fighting for fire fighters and their families,” Robyn Patterson, a White House spokesperson, said in a statement to NBC News.

The Biden campaign also declined to comment on the absence of an endorsement. But a source familiar with the process noted that the union will hold its annual legislative conference in Washington in March, and that Biden has often attended.

Speaking at the same conference earlier this year, Biden talked about how important the group had been in his political career, joking that “there’s three political parties in Delaware: Democrats, Republican and firefighters.”

“Throughout my career, I’ve tried to be there for you all, because you’ve been with me my whole career,” he said at the time.