Democrats in Pennsylvania can almost always count on labor groups to support them in major general elections. But in a pivotal midterm race in the Philadelphia suburbs, many high-powered unions are pledging their support to a Republican.

That could be another red flag for Democrats in Bucks County's First Congressional District, a top target in their campaign to take back the U.S. House that isn't quite going as planned.

U.S. Rep. Brian Fitzpatrick, a freshman GOP lawmaker who has sided with Democrats on some key issues and said he is "extremely disappointed" by a recent Supreme Court decision weakening unions, has raised more than $200,000 from labor groups, according to the website OpenSecrets. His Democratic opponent, multimillionaire philanthropist Scott Wallace, has collected only about $3,000.

Fitzpatrick also won the official endorsement of the Pennsylvania AFL-CIO, an alliance of 45 unions across the state. That's no easy task: Of the 190-plus candidates backed by the group in 2018, only 13 are Republicans. He's received nods from the Pennsylvania State Education Association, AFSCME Council 13, and local firefighters and police unions, too, among others.

"He has a broad base of labor support," said Mustafa Rashed, a Democratic political consultant. "He's not one to be taken lightly."

The First District is exactly the kind of moderate suburban district that Democrats hope they can turn blue this fall. It voted for Hillary Clinton in the 2016 presidential election, and last fall Democrats won seats in Bucks County that had been held by the GOP for more than 50 years. Those factors led the Democratic Congressional Campaign Committee to put Fitzpatrick on its very first "target list" for 2018.

But Cook Political Report, a nonpartisan elections analyst, recently went from describing the race for the First District as a "tossup" to being in the "lean Republican column." One reason: Fitzpatrick has "garnered support from unlikely places," including unions.

"Wallace's wealth, elite pedigree, and out-of-state addresses could backfire" as well, said Cook Political Report's David Wasserman, adding that his "general election efforts have gotten off to a very rocky start."

G. Terry Madonna, a political scientist at Franklin and Marshall College, said that Fitzpatrick's campaign contributions from labor groups aren't as damaging to Wallace as they would be to a typical Democrat, since Wallace has millions of dollars to pour into his campaign. But "it diminishes the enthusiasm gap that the Democrats have," he said.

It means that Fitzpatrick will have union help for "legwork, meet-the-voter work on Election Day," and "he's not going to be overwhelmed by an organized labor that would unite against him."

The First District race also exposes a rift within the labor movement over electoral strategy.

Pro-Fitzpatrick union leaders said he has cast "tough votes" on issues that are important to them. He was one of the Republicans who voted against the GOP's proposed repeal of the Affordable Care Act in 2017, and he recently voted against a farm bill that would have imposed tougher work requirements on food-stamp recipients. He also joined Democrats in defeating a Republican-led effort to weaken the Davis-Bacon Act, which requires most construction workers on federally funded projects to be paid the prevailing wage.

"The labor movement is not a party. It's a movement," said Rick Bloomingdale, president of the Pennsylvania AFL-CIO. "If you're for us, we're for you. And he's been with us, so we're with him."

Fitzpatrick's supporters said he made an effort to build relationships with unions early in his first term, even though labor backed his Democratic opponent in 2016.

"One of the first things he did when he won was reach out to organized labor about having a partnership," said Tom Tosti, president of the AFL-CIO Bucks County Central Labor Council. "You've got to respect that when it comes from somebody after they didn't endorse him."

There may be another rationale for backing Fitzpatrick: If Republicans maintain control of the House, labor groups will keep an ally in the majority. Several unions that haven't endorsed Fitzpatrick have contributed to his campaign, including the International Brotherhood of Electrical Workers.

Wallace has won the endorsement of such labor groups as the United Steelworkers, SEPTA's union, American Federation of Teachers Pennsylvania, American Postal Workers Local 7048 and United Food and Commercial Workers Local 1360.

Wallace's union allies strongly disagreed with the notion that Fitzpatrick is labor's friend, noting he has voted with President Trump 83 percent of the time, according to the website FiveThirtyEight.

"He voted for the tax plan, which hurts our working-class families. That's an inexcusable vote," said Tara Huber, president of Neshaminy Federation of Teachers. "Fitzpatrick may have voted favorably on a few labor issues. But Wallace is going to vote the right way on all of the issues."

Wallace's backers also said that the national AFL-CIO gave Fitzpatrick a rating of only 47 percent in its "legislative scorecard" of Congress members. Every current Democratic member of the U.S. House ranks above that.

"I'm a schoolteacher. Under 70 percent is a failure," said Ted Kirsch, president of the AFT Pennsylvania. Supporting Fitzpatrick, he said, undermines the goal of taking control of at least one house of Congress.

Bloomingdale said the national AFL-CIO's legislative scorecard is an imperfect measure, in part because it's not weighted: "Some issues have more of an impact than others, and that's the struggle with doing a voting record."

He added that there was a time when some Republicans scored 100 percent. Currently, the top GOP score in the U.S. House is 61 percent.

"Unfortunately, the Republican leadership or right-wing philosophy has dragged the party away from supporting workers," said Bloomingdale.