WASHINGTON – The three Pennsylvania Democrats running for U.S. Senate used their endorsements – or lack thereof – as key selling points in their debate Tuesday night.

Katie McGinty, who has racked up establishment support from President Obama to key senators to Gov. Wolf to major labor unions and environmentalists, said their backing speaks to her qualifications.

"I'm proud to have the endorsement of President Obama, but that's because he knows I'm a fighter. He endorsed me specifically because I rolled up my sleeves to go to bat," for the middle class, she said. "I'm also proud of some of the other individuals who are standing with me – I've been on the front lines with janitors, fighting for," a $15 minimum wage.

But in a year when many voters have gravitated to political outsiders, McGinty's two rivals wore their dearth of institutional support as badges of honor.

"People don't trust, rightly, the leaders of either party," said Joe Sestak, citing the many officials who turn to high-paying lobbying jobs after leaving office. The former congressman and admiral said he had not sought any endorsements from political figures because, "there is one endorsement I would like to have, and that's of the people."

Braddock Mayor John Fetterman said he is "not beholden to any endorsement, any special interests."

"I'm simply beholden to the people that I have represented in Braddock that I've represented for the last 11 years and for people all across this great commonwealth," he said.

The exchange was one of the few contrasts on a night when the candidates, at least in person, largely agreed on policy questions such as the Iran nuclear deal and tougher oversight of fracking, or covered old ground on the minimum wage and international trade. The three met in a televised debate at the studios of WGAL in Lancaster.

Gone were the sharp attacks that characterized a previous debate – though the assaults continued on television and in e-mail blasts. In one release, Fetterman's camp derided McGinty's party support as propping up an "uninspiring" candidate whose campaign is depending on more than $3 million of spending by her allies. McGinty's campaign, meanwhile, questioned the outside group spending $750,000 to help Sestak and proclaimed that she has the momentum heading into the April 26 primary.

The Democrats are vying for the nomination to challenge Sen. Pat Toomey (R., Pa.) in a race that could help determine control of the Senate.

Their endorsements also differed when it comes to the presidential contest roiling their party.

McGinty has backed Hillary Clinton. She said at the debate that she is "proud" of both Clinton and Bernie Sanders, but had "the honor" of working with Clinton as a White House environmental aide.

Fetterman backed Sanders, saying the Vermont senator "is where the party is and where the party is going."

Sestak declined to take sides, saying he respects both Clinton – who would be "a very fine commander in chief" -- and Sanders, but that he would not give an endorsement, just as he didn't seek any.

Policy differences were slight. McGinty and Fetterman both blasted international trade deals as bad for American workers, for example. Sestak said he recent deals such as NAFTA and the pending Trans-Pacific Partnership were bad – though he has expressed openness, in general, to international pacts as matters of national security and global influence.

Fetterman's campaign, again in a news release, pointed out that as a Clinton administration aide McGinty had spoken out in favor of NAFTA. McGinty's camp shot back by pointing to her long list of endorsements from labor groups, including the AFL-CIO, who oppose trade deals and have praised her as a champion for workers.

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