READING — Voters could be forgiven for confusing the candidates for the Sixth Congressional District.
The no-nonsense Marine veteran and Harvard MBA who has been raking in contributions from his rich friends around the world? He’s the Democrat.
The affable gay realtor who was elected to the state Legislature straight out of college? He’s the Republican.
The race to represent the congressional district north of Boston has defied stereotypes and expectations all along. The Democrat, Seth Moulton, emerged after his surprise defeat of incumbent US Representative John F. Tierney in the September primary. His win upset the November forecast for Richard R. Tisei, the Republican who had nearly toppled Tierney two years ago and was considered a favorite to win a rematch in a district that was ready for a change.
Now, with Tierney already defeated, change is inevitable, and Tisei and Moulton have been jousting over who would better effectuate that change — the familiar hometown Republican or the dashing newcomer?
“What I’m really running on is experience,” said Tisei. “I can hit the ground running in Washington. I’m in business, so I understand what’s going on in the economy and I’m independent-minded. I have a history of following my own conscience and doing what’s right.”
In a separate interview, Moulton countered: “There’s tremendous enthusiasm for change and with all due respect to Senator Tisei and his 30 years in the Legislature, people aren’t looking for a career politician. We need new ideas, fresh leadership, and that’s why I feel so much momentum on the campaign trail.”
On Friday morning, Moulton was doing the twist with a bunch of very active senior citizens at the Peabody Council on Aging Halloween party. He zigzagged across the dance floor, then made the rounds of the tables, wooing some 300 costumed witches and devils, flappers and cats. The election was four days away.
“It’s great to meet people. I’m having a great time,” he said. While heartened by positive internal polling and public surveys that generally show the race to be close, Moulton said, “I’m going to work hard to earn every vote that I can.”
Moulton, 36, is a first-time candidate running a campaign largely based on biography. A Marblehead native and alumnus of Phillips Academy Andover, he joined the Marines before graduating from Harvard with a degree in physics. He served four tours of duty in Iraq and won two medals for valor for leading his platoon through battles for control of Nasiriyah and Najaf. He returned to earn master’s degrees from Harvard’s Business School and Kennedy School of Government.
Focused on jobs and economic development for the district, and pitching a development district for the city of Lynn, Moulton said his first legislative priority in Washington would be to reform the Department of Veterans Affairs and improve the quality of health care for veterans.
In the 16 months since he became a candidate, Moulton has transformed from a sometimes awkward newcomer to a smooth speaker who shared a stage last week with Vice President Joe Biden.
Since he beat Tierney, Moul-ton has picked up the support of the national Democratic campaign groups whose financial support has helped produce ads, some bitingly negative.
Moulton’s early ads were largely positive, portraying him as a selfless Marine. These days, they target his rival, mulling what Tisei would do in a league with Senator Ted Cruz and House Speaker John Boehner — described as “extremist Republicans” who shut down the government and who want to restrict the rights of women and dismantle Social Security and Medicare.
‘What I’m really running on is experience. I can hit the ground running in Washington. . . . I have a history of following my own conscience and doing what’s right.’
“Richard Tisei and the Washington Republicans: Not our values,”the narrator said in one Moulton ad produced in partnership with the Democratic Congressional Campaign Committee.
It’s a familiar line of attack, however false. In 2012, Democratic ads effectively tied Tisei to a far-right agenda, calling him “Tea Party Tisei.” Voters in the Sixth District had thrown their support to Republican Scott Brown in the US Senate special election in 2010 but did not take a chance on Tisei.
In the current race, Tisei has been intent on getting out ahead of the opposition and defining himself before they did.
“It was so absurd last time that I didn’t think anybody would believe it,” he said. “But the district’s so huge and I do think for a number of people it put up a wall and prevented people from voting for me.”
On Friday morning, Tisei was shaking hands with shoppers coming and going from the Reading Market Basket, getting backslaps of encouragement and pledges of support from onetime constituents who know him by name.
“I just had to wish you luck. We’re really praying for you,” Catherine Palmerino told him before entering the store.
Tisei, 52, who favors abortion rights and gay marriage, hails from a far more moderate wing of the Republican Party. A realtor from Lynnfield, he served 26 years in the state Legislature, a handful as Senate minority leader, before running on the unsuccessful ticket with gubernatorial nominee Charlie Baker four years ago. He came within 1 percentage point of toppling Tierney in 2012.
In the increasingly bitter race this time around, Tisei and Republican allies have attacked Moulton for fund-raising from Wall Street. Moulton calls the attacks “hypocritical,” noting that Tisei has rich friends and Wall Street donors as well.
Notably, this time around, Tisei’s campaign has featured frequent references to his husband, Bernie Starr. In another twist on the stereotypical political script, this Republican campaign is advertising the candidate’s gay marriage.
Arline Isaacson, a political consultant and cochairwoman of the Massachusetts Gay and Lesbian Political Caucus, said those allusions are intended to temper voters’ concerns.
He is telling voters “ ‘I’m not as conservative as you fear,’ ” she said. “. . . The problem is, he’s going to vote for [congressional]leadership which is. And that is a fundamental flaw that he can’t get past.”
Still, in Massachusetts — where most voters are unenrolled and ostensibly open to voting for a candidate from either party — that message is often persuasive.
“I just like what he stands for,” said Jackie King, an independent who pledged her vote to Tisei outside the Reading Market Basket on Friday. “I like that he’s a Republican. But he’s not really a Republican.”Stephanie Ebbert can be reached at Stephanie.Ebbert@globe.com.