Hartford — U.S. Senate candidates Chris Murphy and Linda McMahon thrust and parried Thursday over the familiar subjects of jobs plans and Social Security in their fourth and final debate, yet also touched on the women's vote, their opponent's best qualities and how a Norwegian submarine ended up in a campaign ad referencing Electric Boat.

The late-afternoon debate followed the morning release of a University of Connecticut/Hartford Courant poll that shows Democratic Murphy with a 44 percent to 38 percent lead on Republican McMahon among likely voters, with 17 percent still undecided.

But McMahon maintains an 8-point lead in eastern Connecticut's 2nd Congressional District.

Among women voters statewide, Murphy outpolls McMahon 50 percent to 32 percent. And McMahon leads among men, 45 percent to 37 percent.

The poll of 574 likely voters was conducted from Oct. 11 to Oct. 16 and reports a margin of error of plus or minus 4 percentage points.

The one-hour debate, hosted by the Connecticut Broadcasters Association, was broadcast live from a chandeliered ballroom in the Hartford Hilton Hotel. It featured a more subdued audience than attended Monday's debate at the Garde Arts Center in New London. That evening was notable for the rowdy and disobedient crowd that clapped, catcalled and sometimes drowned out the candidates.

Both candidates stuck to their usual overarching themes Thursday.

McMahon presented herself as a proven job creator with a six-point plan for reviving the economy and lowering unemployment. She portrayed Murphy as a "career politician" who is clueless about the private sector.

Murphy, the current 5th Congressional District representative, described himself as a fighter for the middle class who wants to raise taxes on society's wealthiest to finance education and infrastructure investments and pay down some of the national debt. He painted McMahon as a closet right-winger who would empower a Tea Party-led majority in the Senate.

The candidates gave very different answers to the question of how they define the middle class.

For the purpose of her jobs plan, the middle class is the "spread" beneath the top end of her proposed 15 percent income tax rate (a decrease from the current 25 percent), McMahon said. That rate would top out at $86,000 a year for a single person and $143,000 for a married couple.

"My plan is not about a tax cut for me. My plan is about a tax cut for the middle class," said McMahon, a Greenwich multimillionaire.

Murphy replied that for him, "being part of the middle class is a mentality."

"I think a family that's struggling to make their budget work, who would be in dire straights if they missed a couple paychecks, that's the middle class," said Murphy, who has come under fire in the race for having once skipped rent, mortgage and car payments.

McMahon was asked to specify how she would accomplish her goal of working in a bipartisan manner to keep the Social Security program solvent. The WWE entrepreneur vowed not to support any budget that reduces benefits for current beneficiaries, but she declined to give specifics on what exactly she has in mind for reforms. She said she doesn't mention such details while out campaigning "because they get demagogued."

Murphy offered a cynical retort, arguing that her secret intent is to end Social Security as a program: "She says she's going to get demagogued, that may be another way of saying she's going to lose votes."

Asked for reform specifics of his own, Murphy called for raising the cap that exempts income above $110,000 from Social Security taxes.

"Social Security has 20 years before it starts taking in less money than it sends out, so if you adjust the cap today, you can solve the Social Security issue 20 years from now," he said.

McMahon responded to a question on the veracity of campaign ads by pointing out a current Murphy ad which touts his support for submarine production at EB but uses stock video footage of a foreign-made diesel sub flying a Norwegian flag.

"Those kind of ads just need to be corrected," said McMahon, who is presently airing a rival ad mocking the flag gaffe. "To the people in Groton, I think it was very hurtful."

Murphy's campaign staff have admitted to accidentally using stock footage of a foreign sub.

"I think the fact that Linda McMahon's campaign is reduced to arguing over B-roll footage in our campaign ads shows you how little she wants to talk about the issues," Murphy responded.

There was also disagreement over whether McMahon is truly pro-choice.

"Linda McMahon is not pro-choice," Murphy asserted, noting comments on the Facebook page of a prominent social conservative, Peter Wolfgang, who is voting for McMahon "because her victory could mean the end of Roe v. Wade."

McMahon said Murphy was wrong.

"I will not support my party in repealing any of these laws because I am a pro-choice candidate," she said, adding, "I am an independent thinker, and I will not vote strictly along party lines."

The candidates were later asked to say something nice about the other. Murphy praised McMahon's ambition and her charitable donations. McMahon mentioned the congressman's two sons, ages 4 and 11 months, saying, "They are so cute."

j.reindl@theday.com