Will another incumbent go down?

A primary loss by Rep. John Tierney (D-Mass.) on Tuesday night could actually help Democrats hold onto the contested seat this fall. 

Multiple Massachusetts Democrats said surging challenger Seth Moulton would have a better shot of defeating Republican Richard Tisei in the general election, noting his compelling backstory and lack of a voting record make him a difficult target for the GOP. 

{mosads}Massachusetts Democratic strategist Mary Anne Marsh said that while Tierney’s fate in the general election is still up in the air, Moulton has a clear shot.

“The toughest race for Seth Moulton was always the primary. There is no question if he wins on Tuesday, he wins that seat,” she said.

Many Republicans reluctantly agree. 

“It’s a tougher race for Tisei if he’s up against a fresh face that’s going to get a lot of coverage on every paper in the district, and potentially nationwide,” said Bay State GOP strategist Jeff Stinson. 

While Republicans see Moulton as a strong candidate, Democrats see Tierney as a particularly weak one. 

Last cycle, he barely defeated Tisei — who is openly gay — in a favorable year for Democrats. There was a third-party candidate who drew votes from the Republican as Tierney faced ethics questions stemming from his in-law’s conviction on illegal gambling charges.

Now, Tierney would face both a difficult political climate and a seasoned challenger who has honed his message for the rematch.

The primary itself has been an indication of just how tough a time Tierney would have in November. 

Moulton and groups supporting him have spent more than $1.3 million attacking the incumbent, who launched his first ad less than two weeks before primary election day.

The Democratic challenger has also picked up endorsements from seven of the district’s biggest newspapers, including the Boston Herald and The Boston Globe, with none backing Tierney. 

Three surveys out this past week have shown a tight race. 

A survey from Democratic firm Public Policy Polling conducted for a pro-Moulton group gave Tierney just 47 percent support among likely Democratic primary voters to Moulton’s 45 percent, while one from Remington Research showed it even closer, Tierney taking 43 percent to Moulton’s 42 percent support.And in the surest sign of concern, Tierney last Tuesday began airing an ad attacking Moulton for receiving a contribution from a PAC that has primarily supported Republicans, in an attempt to portray him as conservative. 

Moulton has been on the attack for weeks but hasn’t made colorful details of the gambling ring connected to Tierney’s family his central focus. He said voters don’t need to be reminded about it.

“I haven’t talked about that. I think the voters already know about it,” Moulton told The Hill.

Instead, Moulton is attacking Tierney as out of touch and ineffective, charging in his ads that Tierney only passed one bill during his 18 years in Congress.

“People are ready for change, and they’re ready for new leadership,” Moulton said. 

It’s an argument Tierney hasn’t yet given a clear answer to and one that’s proven particularly potent in a year when anti-incumbent sentiment is surging nationwide.

It’s also a line of attack that Tisei’s spokesman, Charlie Szold, said the challenger plans to use against the Democrat, whoever that is.

“Richard is the only one in the race who has an actual history of bipartisan accomplishment,” he said.

But national Republicans are stumped when asked how they would handle Moulton in the general election.

“That’s to be determined,” said one national Republican strategist engaged in House races, when asked what their argument against Moulton would be. “Moulton versus Tisei? I don’t think the narrative is there yet.”

Their admitted lack of a clear message against Moulton is exactly why many Democrats in the state are rooting for him on election day.

National Democrats, however, wouldn’t entertain questions about the potential for a Tierney loss and the aftermath, insisting they’re confident he’s safe and will go on to win in November.

“John Tierney is a tireless advocate for Massachusetts families, and voters have proven they support his commitment to the middle class over Richard Tisei and his out-of-touch agenda,” said Democratic Congressional Campaign Committee spokesman Josh Schwerin.

Tierney has some establishment support, including the endorsements of Sen. Elizabeth Warren (D-Mass.) and most of the Massachusetts delegation, as well as campaign help from House Minority Leader Nancy Pelosi (D-Calif.). But no outside groups, including the national party, have spent for him yet. 

The incumbent was taking no chances going into Tuesday. He bought another $120,000 in airtime for the final few days of the race, enjoys the organizational support of some of the district’s biggest unions and had get-out-the-vote events this weekend with Massachusetts Democratic Reps. Joseph Kennedy and Michael Capuano, along with former Rep. Barney Frank.

It’s that institutional support and organizational advantage that have most Democrats predicting that, though Tierney is vulnerable, he’ll likely eke out a win on Tuesday.

“Can Seth match [Tierney’s organization]? I don’t know,” Marsh said. “He’s done all the right things, raised all the money, built an organization, is generating the kind of attention and momentum that you need in this [get-out-the-vote] period going into Tuesday … but is it too little too late?”

Either way, however, Republicans are calling it a win. The expensive, and at times nasty — each candidate has called the other a liar over the past week — primary fight will leave the ultimate nominee with less money in his campaign coffers and more negative poll numbers than he would have had without the contest.

“It looks [as if] whoever wins, he’s going to be pretty damaged coming out of that primary; the closer it is the better,” the national Republican said. “The fact [that]an 18-year incumbent is in this much trouble in a primary speaks volumes.”