Representative Seth Moulton, in a sign of growing discontent with the direction of the Democratic Party, on Tuesday became the second member of Massachusetts’ congressional delegation to throw his support behind Representative Tim Ryan’s upstart bid to oust Nancy Pelosi as Democratic leader of the House.

The announcement from Moulton, a 38-year-old former Marine, cements his reputation for bucking party leadership, two years after he defeated veteran congressman John F. Tierney in a hard-fought primary.

But it also poses some risks. Moulton said Tuesday that it’s possible he could lose his coveted seat on the House Armed Services Committee if Pelosi wins reelection as leader on Wednesday morning.

Still, he said, he believes Ryan, a 43-year-old former high school quarterback from northeast Ohio, would give the party a better chance to regain the majority by appealing to working-class voters from the industrial Midwest who supported Donald J. Trump for president.

“Voters sent a very clear message to our entire party that the status quo is not working and, as Democrats, we’ve got to come to terms with the fact that we need a new strategy,’’ Moulton said in an interview Tuesday.

He joins Representative Stephen F. Lynch of South Boston, a former ironworker who said Monday he would back Ryan.

“This last election was an epic failure and another lost opportunity,’’ Lynch said in a statement Monday. “To continue with business as usual would be a betrayal of our Democratic values. I honestly believe that with Tim Ryan as Democratic leader, we can demonstrate to middle-class workers that we really do care about them, too.’’

Pelosi, 76, who represents San Francisco and has been party leader since 2003, has said she has the support of two-thirds of the Democratic caucus, enough to win reelection as party leader when members vote by secret ballot on Wednesday morning.

But Ryan told CNN on Tuesday that he is “within striking distance,’’ and believes his message — that Democrats must focus squarely on economic issues and not on patching together coalitions based on race and gender — is resonating.

Moulton said Ryan would give the party a “fresh face’’ who knows how to win elections in the Midwest.

“He’s made clear he’s going to lead a caucus-wide effort to spend time out there in union halls and pizza parlors and bars and legion posts, understanding what’s really on the minds of these voters, especially voters who are historically Democrats but supported Trump in the election,’’ Moulton said.

The other members of Massachusetts’ nine-person delegation have endorsed Pelosi, with the exception of Representatives Michael E. Capuano and William R. Keating, who have not stated their choice and did not respond to messages on Tuesday.

Earlier this month, Moulton was part of a group of House Democrats who pressured the caucus to delay the leadership vote, which allowed for Ryan to formally announce his candidacy.

Moulton said he wishes both Ryan and Pelosi had more time to flesh out their strategies to lead Democrats out of the political wilderness.

“She may win reelection,’’ he said, “but there’s no question that this discussion has prompted some real introspection in our party that, regardless of the result tomorrow, has to continue if we have any chance of being successful.’’

Michael Levenson can be reached at mlevenson@globe.com. Follow him on Twitter @mlevenson.