An anti-union construction trade group is targeting three vulnerable House Republican freshmen with a barrage of negative advertising over a series of labor-friendly votes.

Reps. Jon Runyan (N.J.), Joe Walsh (Ill.) and Robert Dold (Ill.) already face tough re-election battles that could be complicated by a spate of online ads from the Associated Builders and Contractors accusing them of breaking campaign promises.

The trade association, which helped fuel the Republican takeover of the House in 2010 with more than $1.1 million in campaign contributions, is trying to counter an executive order issued by President Barack Obama it contends gives unionized contractors an unfair advantage in bidding wars for federal projects.

The House will vote next week on language that would bar federal agencies from requiring outside contractors to agree to a single set of employment standards for a construction project. The pacts are known as project labor agreements.

The measure is modeled on legislation introduced by Rep. John Sullivan (R-Okla.) that the association helped write and could come up as part of the military construction authorization bill as soon as Thursday.

The association says all three Members pledged to support such legislation in a 2010 questionnaire. Since coming to Washington, D.C., they seem to have had a change of heart.

“Getting here and doing the exact opposite led us to take an action that we normally wouldn’t: taking ads out against the Republican Party,” said Geoff Burr, the group’s senior vice president for federal affairs.

The association wrote checks to Runyan and Dold for a combined $12,000 last cycle, but this time around it has given only $3,500 to the pair, according to the Center for Responsive Politics.

Walsh, however, has never benefited from the group’s largesse and his office came out swinging at the ad campaign.

“Congressman Walsh has never promised anything to ABC,” said Justin Roth, Walsh’s chief of staff, said in a statement. “He has told them the same thing that he has told labor groups. Which is he does not support the government mandating or prohibiting the use of PLA’s. … If there was a vote to make PLA’s mandatory he would oppose it, just as he votes against measures to forbid them.”

The ads, which will run through the end of next week and cost more than $100,000, also target Reps. Judy Biggert (R-Ill.) and Mike McIntyre (D-N.C.).

Supporters of the PLAs say they streamline complex projects, ensuring a constant supply of qualified workers and mitigating on-site conflicts over who does what job.

Tom Owens, a spokesman for the building and construction department of the AFL-CIO, said that non-union companies can still win contracts under the agreements and that the ABC is just trying to weaken organized labor.

“All they do 24/7 is advance stuff that’s going to whack unions,” he said. “They are more or less a political and ideological organization.”

Union lobbyists worked hard to line up support on the issue and trumpet the fact that 28 Republicans voted with them when the House took a similar measure up earlier this month as part of a defense authorization bill. Although the amendment, introduced by Rep. Roscoe Bartlett (R-Md.) passed, none of the five targeted Members supported it.

“Since my election to Congress, my priority has been to preserve and create jobs in South Jersey,” Runyan said in a statement to Roll Call. “Those principals have guided me and will continue to guide me as the House considers legislation.”

Dold did not respond to requests for comment.

The House has voted on the language four times this Congress, but the construction trade association has logged only that one victory.

Obama issued the executive order soon after taking office, encouraging agencies to require the agreements in contracts for federal projects. Former President Bill Clinton had issued a similar order, but it was reversed by the administration of former President George W. Bush.

“We’ve seen an increase in PLAs mandated by federal agencies as a result of the Obama executive order,” said Ben Brubeck, who is another lobbyist at ABC. “It’s clear the real intent of the order is to steer federal construction contracts and jobs to his political supporters.”

Since 2009, the construction trade group has helped its members successfully overturn bids that required the agreements on four different projects: a Veterans Affairs medical center in Pittsburgh; an Army Corps of Engineers project in Camden, N.J.; a General Services Administration project in Washington, D.C., and a Department of Labor Job Corps Center in Manchester, N.H.