McLEAN, Va. — Democrat Tim Kaine and Republican George Allen met today in their third debate of the long campaign for Virginia’s open Senate seat.

The two former governors touched on themes prevalent on the campaign trail — health care, defense sequester cuts, taxes and the economy — and drew a clear line in the sand for the independent Northern Virginia voters, who will play a determinate role in the outcome of the race.

“Folks, there’s a clear choice in this Senate election, in which approach is going to be best for jobs here in our country,” Allen said in his closing remarks.

The debate, hosted by the Fairfax County Chamber of Commerce and NBC-4, came a day after two public polls showed Kaine for the first time pulling out to a significant lead over his Republican opponent. The two have been tied since Kaine entered the race about 17 months ago, and both Allen and Kaine downplayed the polling results to reporters after the event.

Kaine told reporters that he believes the voters still undecided in this race are looking for someone who will be open to working across the aisle to fix a gridlocked Senate. That’s a theme he touched on several times during the debate and something he often mentions on the campaign trail.

“We need more bridge builders. We need more people that know how to listen and find common ground,” Kaine said during the debate. “That’s the one thing we’re missing in Congress right now, and we’ve got to put people in place that have a demonstrated track record of being able to do it.”

Allen said voters need only look at his record “as a governor as well as United States Senator to make this country more competitive for an investment in jobs in Virginia.”

Kaine was asked about his stance on gay marriage and pushed by moderator David Gregory, host of NBC’s “Meet the Press,” whether he agreed with President Barack Obama, who came out in favor of legal same-sex marriage. Kaine said state legislatures should be able to decide the legality and exact definition of it, and he indicated he would have no problem with it as long as the result was full equality.

Allen was pressed by Gregory about whether he agreed with Republican presidential nominee Mitt Romney’s comments at a fundraiser in May about the 47 percent of Americans who do not pay federal income taxes.

“I look very positively at the people of Virginia,” Allen said. Asked again whether he agreed with Romney’s description of them as victims, Allen said, “I have my own point of view.”

On the same question, Kaine was asked whether everyone should pay federal taxes, no matter their income. Kaine said he would be “open to a proposal that would have some minimum tax level for everyone, but I would insist many of the 47 percent that Gov. Romney was going after pay a higher percentage of their income to taxes than he does.”

Some of the sharpest exchanges came over the looming automatic spending cuts to defense, which would have a major effect on jobs in the Old Dominion.

Allen, who did not support the agreement last year that allowed for the debt ceiling to be raised, said repealing and replacing President Barack Obama’s health care law would be one short-term solution to balancing the budget without the cuts to the defense industry, and that a balanced budget amendment is the long-term solution.

“Tim said in the last debate that this was the right thing to do,” Allen said. “Now he comes up with a plan, he says.”

After Allen asked whether Kaine had done an analysis on the effect his plan to avoid the cuts would have on jobs, Kaine said: “I do have a plan. And the plan is a compromise, and it’s specific, unlike anything I just heard in the last 90 seconds.”

Kaine said letting the temporary cuts expire for those making more than $500,000 a year, fixing Medicare and ending the subsidies for the big five oil companies would cut much of the trillion dollars necessary.

The outcome of this race for the seat of retiring Sen. Jim Webb (D) is crucial to control of the Senate, and both campaigns expect a tight battle for the next 47 days. Webb advanced to the Senate six years ago by defeating Allen.

The debate, broadcast live on NBC, will be rebroadcast on Sunday at noon. The candidates will meet for two more debates before the general election: Oct. 8 in Richmond and Oct. 18 at Virginia Tech in Blacksburg.