LYNN—US Representative John F. Tierney and his Republican challenger, Richard R. Tisei, sparred over taxes, Washington gridlock, and the future of the middle class in a surprisingly civil debate that was notable for what was never mentioned: how much Tierney might have known about the illegal gambling ring that was run by his wife’s brothers.

Controversy surrounding the gambling ring has made the race one of the most competitive and bitter in Massachusetts. A Republican political action committee that backs Tisei is running ads demanding that Tierney, an eight-term Salem Democrat, “man up and tell the truth — the whole truth,” about the gambling business.

But in their first debate, Tisei, a former state senator from Wakefield, did not mention the issue. Speaking to reporters after the debate, he said he wanted to respect the organizers at MassINC, a think tank, who wanted to keep a strict focus on policy. Still, MassINC officials said the candidates were free to bring up any issue.

Advertisement - Continue Reading Below

In a face off that was more an exchange of quips than knockout blows, neither candidate appeared to sway a crowd of several hundred that seemed evenly divided among Tierney and Tisei supporters.

Most of the hour-long debate, held at North Shore Community College, focused on which candidate would be able work effectively in a highly polarized Congress.

Tisei blasted Tierney as a partisan Democrat who has been unwilling to work across the aisle.

“For all people who are frustrated with Washington gridlock, I ask you: what will change if John Tierney is reelected?” Tisei said.

Tierney repeatedly underscored his main theme: that Tisei is backed by conservative “Young Guns” in the House and will vote to put “ideological extremists” such as Virginia Representative Eric Cantor into the leadership. He mentioned several times that Tisei has called the Tea Party a “godsend” and has labeled the deep spending cuts and sweeping Medicare changes proposed by Representative Paul Ryan a “good start.”

“Unfortunately, my opponent has sided with that group, with the Young Guns,” Tierney said.

Daniel Fishman, a Libertarian candidate, also participated in the debate. He called himself an “average guy” with “a voice that is neither Republican or Democrat, but of the people.” Though he was seated between Tierney and Tisei at a long table, however, he was mostly ignored by the other two candidates.

Rebutting Tierney’s charges that he will empower conservative Republicans in the House, Tisei frequently cited Democratic policies he supports. He said he backed President Obama’s executive order that suspended deportations for young illegal immigrants. He praised Governor Deval Patrick for supporting community colleges.

Tisei also promised to vote against Ryan’s budget and bragged that, when he was in the state Legislature, he voted against Governor Mitt Romney 46 percent of the time.

“I have a record of being able to work with Democrats to get things done, and that’s exactly what we need in Washington right now,” said Tisei, who served for 26 years in the Legislature.

But Tierney countered that many of the issues Tisei promises to work on – such as overhauling immigration – would be sidelined by House Republicans.

The two candidates’ sharpest disagreements centered on Medicare and taxes. Even though Tisei said he would vote against Ryan’s budget, Tierney accused Tisei of wanting to “voucherize” Medicare. Tisei assailed Tierney for supporting Obama’s health care law, which calls for a $700 billlion reduction in the growth of the Medicare program. Tisei called that a “cut” in Medicare, a charge Tierny called the “biggest lie in the century.”

On taxes, Tierney said he wants to let the Bush tax cuts expire for the wealthy. Tisei said he wants to extend them for all income levels. Tisei said he also wants to repeal the medical device tax, which he said is hurting a number of companies in the district. Tierney said industry agreed to that tax as part of Obama’s health care law.