Some labor leaders are indicating they’re willing to look past Rep. Stephen Lynch’s (D-Mass.) once-contentious “no” vote on healthcare reform and support him in his bid for the U.S. Senate.

Lynch was one of a few dozen Democrats who voted against the healthcare reform bill when it was passed in the House in 2010 — even after he was personally lobbied by AFL-CIO President Richard Trumka to vote for in favor of President Obama's signature legislation.

"We have a scorecard, some are more important than others," Trumka said at the time. "This is a very important vote because this is the future of the country."

That year, Lynch faced a primary challenge from Mac D’Alessandro, who served as the New England political director for the Service Employees International Union, in a race which prominently featured the Lynch vote against healthcare.

Lynch defeated D’Alessandro handily, but the former challenger said he believed healthcare could play an even larger role in the coming Senate race now that Massachusetts residents have seen what reform has accomplished.

“The enactment of the law was actually too new [in 2010], and a lot of people didn’t know what was in the law,” D'Alessandro said. “Now that we’ve seen some of the benefits start to accrue to people, perhaps those issues will become the subject of debate again.”

Lynch is battling Rep. Edward MarkeyEdward (Ed) John MarkeyDemocrats lay into Trump's pick of Bolton for national security adviser Dem senator on Bolton hire: Trump is 'lining up his war cabinet' Trump replaces McMaster with Bolton as national security adviser MORE (D-Mass.) for the Democratic nomination to run in a special election to replace John KerryJohn Forbes Kerry2020 Dems compete for top campaign operatives Kentucky candidate takes heat for tweeting he'd like to use congressman for target practice Breitbart editor: Biden's son inked deal with Chinese government days after vice president’s trip MORE in the Senate. Kerry is leaving the upper chamber to join the Obama administration as secretary of State.

Markey is expected to try to make the healthcare vote an issue in the primary. He is banking on the reasoning that Democratic voters tend to be more liberal and thus would take greater issue with a candidate that opposed President Obama’s signature legislation, which was inspired by Massachusetts’s own healthcare system.

But a number of union leaders in Massachusetts have indicated Lynch’s union background could outweigh that vote, at least within the labor community. Lynch was an ironworker and served on the Iron Workers Union board and as a union advocate.

“I think we've moved beyond that. We had our difference of opinion on that. It got pretty hot and heavy on the way, but this time we're starting from fresh,” said SEIU Massachusetts State Council Executive Director Harris Gruman.

Frank Callahan, president of the Massachusetts Building Trades Union, said that he expects the members of the State Building Trades Council to vote to endorse Lynch, though they haven’t yet met to officially address the race.

The healthcare vote, he said, was in the past.

“The bill passed. He took a position on that. We disagreed with him, but there are a number of other issues,” Callahan said.

“He’s not only voted for [our interests], but he's lived as someone who's been a union worker.”

Lynch stands by his opposition vote. He told The Hill on Thursday that the unions were coming around to his position and that he had discussed the issue with labor leaders numerous times since his vote.

“A lot of them have had a change of heart” on the healthcare law, he said, citing a Wall Street Journal report out Thursday indicating some unions are frustrated with the potential effects on hiring from implementation of the law.

Lynch also told The Hill that he had secured the endorsements of 27 unions in Massachusetts, and was working to get the backing of the Massachusetts AFL-CIO.

While Lynch’s union background may be a strong selling point for organized labor in the state, the unions may also be more willing to support him because of a feeling that they were snubbed by the Democratic Senatorial Campaign Committee in its endorsement of Markey, Lynch said.

“When Mr. Markey was nominated or selected by the DSCC, they didn’t talk to labor … They were downright furious that no one had ever talked to them about who the selection would be. So, knowing that and knowing how angry they were, I tried to get around to every single labor leader in the state to ask them to support me, while my opponent did not,” Lynch  said.

Markey was the first to announce his candidacy for the seat, and soon thereafter received a number of prominent endorsements, including from Kerry himself, and the Democratic Senatorial Campaign Committee. 

The DSCC declined to comment about Lynch's remark. 

But Markey's campaign rebuked Lynch. 

"This charge is just plain wrong. Rep. Markey has been talking with labor leaders across the state, and he will continue to do so throughout this campaign," said Giselle Barry, a campaign spokeswoman. 

"He has a strong record of standing up for working people. He also continues to be in touch with environmentalists, small business owners, grassroots activists, and many others, and he is encouraged by the response he is receiving for his campaign."

Labor played a large role in Sen. Elizabeth WarrenElizabeth Ann WarrenWarren battles Carson: Housing discrimination 'the scandal that should get you fired' Overnight Regulation: Omnibus includes deal on tip-pooling rule | Groups sue over rules for organic livestock | AT&T, DOJ make opening arguments in merger trial Warren presses Mulvaney, Azar on tip pooling MORE’s (D-Mass.) 2012 victory over Republican Scott Brown, turning out thousands of volunteers throughout the course of the 2012 election. While labor leaders insist they’ll be ready to engage at the same level during the special election, some have privately expressed concerns that their members are somewhat tired out from the last cycle.

One Massachusetts labor leader, who asked not to be named in order to speak frankly on the topic, said some union leaders were, as Lynch said, chagrined at what they saw as a snub from the national party.

“We did a tremendous amount of work, and a tremendous amount of good work, for Elizabeth Warren in the labor community. People were upset. We felt that we earned a seat at the table, and we weren’t a part of it,” the labor leader said.

However, Gruman said he hadn’t heard similar grumbling from the members of the Massachusetts SEIU. He added that the union hadn’t expected to have any say in that nominating process, but that there may be pushback against party involvement in the primary.

- Updated at 11:15 a.m. and 12:05 p.m.