Maybe it’s the better-than-expected jobs report. Maybe it’s Mike Bloomberg coming down from his royal throne to endorse Barack Obama. Maybe it’s the hurricane cleanup or the candidates racing to last-minute rallies in Ohio and Wisconsin.

But there is a growing sense that the photo-finish presidential election could tilt either way, that a late development could make all the difference.

Friday morning’s unemployment figures—issued without objection from Jack Welch—were basically good news for a president who has presided over an anemic economic recovery. The creation of 171,000 jobs in October (about a third more than expected), combined with revised estimates that an additional 84,000 jobs were created in August and September, provides a sense that a fragile recovery is finally taking hold.

On the other hand, the top-line figure—unemployment ticking up to 7.9 from 7.8 percent—gives Mitt Romney’s team the talking point that joblessness is worse than when Obama took office.

Does Bloomberg move any votes outside of New York City? Who knows? But his argument that Obama is far preferable on climate change could resonate at a time when Hurricane Sandy is the latest in a line of increasingly violent storms. And the mayor’s jab that he would have happily endorsed the Mitt Romney of 1994 or 2003 plays nicely into Obama’s “Romnesia” mockery.

For what it’s worth, things seem to be breaking Obama’s way in these final days. But a victory is far from assured.

With the Midwest at stake, the president has been talking about the auto bailout virtually every day. And Romney may have blundered with an ad that says Obama sold “Chrysler to Italians who are going to build Jeeps in China.” Technically true, but highly misleading in its insinuation that American jobs are being moved overseas. Chrysler has expanded production of its Jeeps and is also starting to build them in China for that market. The heads of Chrysler and General Motors have both criticized the ad.

In Ohio on Friday, Obama said: “You got folks who work at a Jeep plant who have been calling their employers, worried, asking ‘Is it true that our jobs are being shipped to China?’ The reason they are making these calls is because Governor Romney ran an ad that says so. Except it’s not true. Everybody knows it’s not true. The car company themselves told Governor Romney to knock it off.”

As if to underscore how important the auto rescue is in Ohio, the Toledo Blade’s lead story Friday was headlined: “Detroit residents still angry with Romney’s anti-bailout stance.”

Obama left the tougher stuff to a top surrogate, former Ohio Governor Ted Strickland, who declared that Romney and Paul Ryan “don’t even know how to fake compassion.”

Romney, also in Ohio, was driving his message that the administration had failed to fix the economy. “The same course will not lead to a better destination,” he said. “Unless we change course, we may well be looking at another recession.”

Heading into the final weekend, prognosticators were looking at polls even more intently than usual, which is to say every five minutes instead of at half-hour intervals.

A Washington Post/ABC tracking poll could hardly be closer: 48.56 percent for Obama, 48.49 percent for Romney. No wonder both sides are sending armies of lawyers into key states for election monitoring and possible recount battles.

In Ohio, a CNN survey gives Obama a 50 to 47 percent lead, not exactly safe, given that the election could turn on the Buckeye State.

In Colorado, Obama has leads of two and four points in a pair of surveys and is tied with Romney in a third.

In New Hampshire, the president has a six-point lead in one poll but only a one-point edge in another.

In Virginia, two polls give Obama a lead of three points and one point, respectively.

And Reuters has Obama up by two points in Florida, a state that had seemed to be trending Romney’s way.

Bottom line: Romney isn’t leading in any of those states. But nor has the president put them away.

Nate Silver, the New York Times blogger and polling guru, responds to critics of his decision to call Obama a strong favorite thusly:

“The argument we’re making is exceedingly simple. Here it is:

“Obama’s ahead in Ohio.

“A somewhat-more-complicated version:

“Mr. Obama is leading in the polls of Ohio and other states that would suffice for him to win 270 electoral votes, and by a margin that has historically translated into victory a fairly high percentage of the time.”

Dick Morris has already predicted that Romney will win in a landslide. But now the Fox News pundit appears to be backtracking a bit:

“A danger signal comes from the latest Rasmussen Poll reflecting a two-point gain for Obama. Whereas before the storm, Rasmussen showed Romney two ahead, he now has the race tied at 48-48.

“That is troublesome.”

If Romney loses, the GOP can blame it on Hurricane Sandy. And maybe Chris Christie. But there are three full days of campaigning left.