Former Vice President Joe Biden is being accused of neglecting a major Pennsylvania labor union, even as he positions himself as the best candidate to win back the Keystone State in 2020.

The Philadelphia chapter of the AFL-CIO lambasted Biden on Friday for ignoring an invitation to attend their presidential town hall in September. The union hopes the event, which has already drawn the attention of seven other presidential candidates, will make the case that Democrats cannot take organized labor for granted anymore.

“He always calls himself a Pennsylvanian at heart. His headquarters are here in Philadelphia. But his folks haven’t found the importance of coming together and talking to our workers,” Pat Eiding, the group’s president, told NPR. “And so that’s very disappointing.”

“There’s got to be some respect for the working people, if they want their vote,” he added.

Eiding and his union, which numbers more than 150,000 members, is a major player in Pennsylvania’s Democrat electorate. In previous years, the group’s support has been vital for any candidate hoping to coalesce Pennsylvania’s large population of union workers—which accounts for more than 12 percent of the state’s entire workforce—in their favor.

Apart from potentially skipping out on the town hall, Biden has angered the union for signaling that he prefers the company of high-powered and moneyed corporate interests over its membership. Eiding cited the fact that Biden attended a fundraiser at the home of a senior Comcast executive only hours after proclaiming himself a friend of unions when announcing his presidential campaign. The telecommunications giant has been accused by labor leaders of “systemically squeezing out unions.”

“Our good friend Joe Biden, from down the road a bit, he makes his announcement in Philadelphia,” Eiding said. “First place he goes is [the home of] the head of Comcast. No connection with labor. And they go forward. And it was a little disturbing because I thought, ‘Well, here we go again.’ ”

All of that seems to have raised concerns from organized labor about Biden’s bonafides. Since jumping into the race, Biden has sought to distinguish himself as the “working-class” candidate that can bring manufacturing states like Pennsylvania and Michigan back into the Democrat’s camp after both went for Trump in 2016. Part his of strategy has entailed courting labor unions that make up a sizable chunk of the electorate in such states.

“I make no apologies. I am a union man,” Biden told a crowd in Pittsburgh, Pennsylvania, shortly after launching his candidacy. “The country wasn’t built by Wall Street bankers, CEOs and hedge fund managers, it was built by you.”

Despite the rhetoric, not everyone is sold, as evidenced by Eiding, who is pushing his union not to endorse any candidate just yet.

Compounding the problem is that the nearly 700,000 union workers in Pennsylvania are no longer certain to vote Democrat in the general election. In 2016, President Donald Trump received the backing of more than 200,000 of Pennsylvania’s union workers. The support was likely decisive in helping Trump eke out a win over former Secretary of State Hillary Clinton statewide by less than 45,000 votes. Trump’s victory was the first time a Republican had carried the Keystone state at the presidential level since 1988.

The president’s results in Pennsylvania were mirrored across the country. The Cooperative Congressional Election Study conducted by a consortium of 99 universities estimated that about 38 percent of union members nationally voted for Trump in 2016. The AFL-CIO’s own analysis found that Trump did substantially better among the group’s membership than Mitt Romney in 2012.

Some have even speculated that Trump’s strong support with union workers, likely the result of his economic nationalism, was the key to winning traditional Democrat states like Michigan and Wisconsin.