After today’s final debate, just two weeks remain. Expect President Barack Obama and Republican challenger Mitt Romney to supercharge their ground games in a last-ditch effort to close the deal with voters.

Tightening polls suggest neither one has been able to complete the job yet.

Polls often shrink just before a presidential election as undecided voters jump off the fence. And late-deciders often break for the challenger when an incumbent is running.

Debates have played an outsized role this year — both in deciding the Republican primaries and now in bringing the presidential choice into sharper focus for many Americans.

But with no further debates and barring an unforeseen “October surprise,” one of the few remaining uncertainties is the government’s release of this month’s jobs report just four days before the election.

The September report showed a sharp unemployment rate drop to 7.8 percent, dipping under 8 percent for the first time since the start of Obama’s presidency. Was that an aberration or is the jobs picture really improving?

The October report could tell us — although it won’t matter to the many who have already voted early.

Romney joked that Obama’s latest campaign slogan is “you’re better off than you were four weeks ago.”

Falling jobless rates helped both Presidents Ronald Reagan and Franklin D. Roosevelt win reelection, even though unemployment rates were still high — but dropping. Momentum counts for a lot in politics.

Unemployment declined over the past year in eight of nine battleground states. Ohio added the most jobs. Wisconsin was the only battleground state to lose jobs.

But Romney’s selection of Wisconsin Rep. Paul Ryan as his running mate is helping to make the state more competitive for Republicans.

Vice President Joe Biden campaigned today in Ohio and Ryan in Colorado — both essential battlegrounds.