In their final and most free-wheeling debate, Senate rivals Gabriel E. Gomez and Edward J. Markey vigorously challenged one another’s record Tuesday, dropping many of their canned lines during a series of fast-moving and often heated exchanges about Gomez’s business background and Markey’s tenure in Washington.
With just a week remaining until the special election, both candidates sought to break through the volley of accusations they lobbed at one another to make their closing arguments to voters.
Gomez, the Republican nominee, is trailing in the polls and in need of a jolt to shake up the race. He all but pleaded with voters to give him a shot at serving the remainder of John F. Kerry’s Senate term.
“I ask you to give me 17 months, and see if I’ve kept my word,” he said in his closing statement. “And if I have, then you can reelect me. And if I haven’t, then vote me out.”
He repeatedly argued that electing his Democratic rival to the Senate, after 37 years in the House, would only continue the gridlock in Washington.
“Nothing’s going to change if Mr. Markey wins this election,” Gomez said. “We’re going to have the same D.C. down there and the same dysfunction. The only thing we’re going to have is him moving from one building to the next.”
Markey sought to strike notes of economic populism, arguing that Gomez would slash Social Security and roll back regulations on Wall Street and that he was out of step with Massachusetts voters in opposing an assault weapons ban.
“This is really a question of whose side you’re on, who you’re going to fight, what you’re going to stand up for,” Markey said. “And I think my record is clear, and I think in the course of this campaign we’ve learned who Mr. Gomez is going to fight for.”
The debate, the third of the truncated campaign that ends Tuesday, also reached the widest audience, broadcast by a media consortium that included WGBH-TV, NECN, WCVB-TV, and WHDH-TV.
Some of the toughest exchanges came when both candidates were allowed to question one another directly, an opportunity that both seized upon to highlight one another’s perceived weaknesses.
Markey, continuing his focus on Gomez’s opposition to an assault weapons ban, asked the Republican why a civilian would need a gun that can shoot 100 bullets in less than two minutes. When Gomez evaded a direct answer — instead highlighting his support for expanded background checks for gun buyers and accusing Markey of politicizing the issue — the congressman pounced: “Mr. Gomez, you haven’t answered the question,” he said.
Gomez retaliated with a question about Markey’s support for tax increases, asking if he had ever once defied Democratic leadership to oppose a tax hike. Markey did not answer directly, instead saying he has backed tax increases on the rich and on corporations and cuts for the middle class.
Gomez jumped in. “So just to be clear: In 37 years, you couldn’t find one time to go against your party to not vote to raise taxes,” he said.
The two candidates also squared off over Gomez’s decision to campaign with John McCain, a five-term senator, despite Gomez’s support for term limits for senators.
“Did you ask John McCain to leave the Senate?” Markey said. “No, Mr. Gomez, you did not.”
But Gomez argued that he did, in fact, tell McCain he should be barred from running for another term.
“I did tell Senator John McCain that he should be term-limited,” said Gomez, who supports a two-term limit.
Markey was incredulous. “That conversation did not happen,” Markey said, his voice dripping with skepticism.
“Are you calling him a liar?” said the moderator, R.D. Sahl, a former television news anchor.
“I’m saying that did not happen,” Markey said.
A McCain spokesman, Brian Rogers, sent an e-mail last night saying, “Senator McCain did discuss the issue of term limits with Gabriel Gomez when they campaigned together last month. They disagree on this particular issue, but agree on many others.”
Sahl pressed Markey on his residency, asking him why his home address was blacked out on tax returns he has released to the public. Republicans have argued that after nearly four decades in Congress, Markey is a de facto resident of Maryland, where he owns a large home, not Malden, where he has a more modest house.
“Oh, it is Massachusetts” that was redacted on the tax returns, Markey said. He insisted that blacking out the address was an accountant’s mistake. After the debate he told reporters he would release an unredacted version of his tax returns Wednesday.
It was Gomez’s turn to be put on the spot again when Sahl asked how voters can trust him when he will not discuss details of his 16 years as a private equity investor. Gomez said he worked on public-sector retirement funds and “at great companies in the private sector” and said President Obama is an investor in his firm, Advent International.
But he did not name any specific companies, giving Markey an opening to attack.
“We are still waiting to find out who he worked for,” Markey said. “What are the names of those clients? It’s important! My voting record is completely transparent. People know every vote that I’ve cast over the years. But with Mr. Gomez, we still don’t know who his clients were, who he worked for.”
Sahl added pressure to Gomez, telling him, “I’m going to come back to the question because, frankly, you didn’t answer it.”
When the topic emerged again, Gomez mentioned that he has worked with Lululemon, the athletic clothing firm. But he declined to delve deeply into his business record.
“If Congressman Markey wants to compare resumes, I’m more than happy to do that, congressman,” Gomez said. “And if you knew what private equity was, you’d know that we don’t have clients. It’s that simple. We have investors.”
Joshua Miller of the Globe staff contributed to this report. Michael Levenson can be reached at mlevenson@