Many commentators will judge who won tonight’s debate by asking whether Mitt Romney showed he can “connect” and “empathize” with regular Americans or whether Romney had a game changing “moment” or whether Romney got Obama to botch his defense of his economic record. But here’s another way to judge the proceedings.

It is suggested by the Romney campaign’s new direct-to-camera ad, in which Romney paints a grim picture of the Obama economy and claims his plan will succeed where Obama failed:

In the ad, Romney says (emphasis mine):

“Too many Americans today are struggling — living paycheck to paycheck. More Americans live in poverty than when President Obama took office. We should measure our compassion by how many of our fellow Americans are able to get good paying jobs, not by how many are on welfare. My economic plan will get America back to work and strengthen the middle class. I’m Mitt Romney. I approve this message because we can’t afford another four years like the last four years.”

I say we judge Romney’s performance based on how convincingly, and with how much specificity, he backs up that one sentence — on how convincingly he demonstrates that his “economic plan will get America back to work and strengthen the middle class.” Those are his words. If he fails to persuasively back them up, little else will matter.

Here’s why. As many have noted, the pressure is on Romney, and not on Obama, to use tonight’s performance to change the basic dynamics of the race. Those dynamics are as follows: Romney does not hold an advantage on who is more trusted on the economy. Romney no longer enjoys the presumption of economic superiority based on his business background and on the fact that he represents an alternative to disappointment with Obama. Romney has failed to persuade voters to base their choice solely on their dissatisfaction with the status quo or on whether they are better off than they were four years ago.

The new NBC/WSJ poll tells the story. It finds that 53 percent say the nation is on the wrong track. But it also finds Obama and Romney tied on the economy — and finds that Obama holds a commanding lead, 48-35, on who is more prepared to lead the country for the next four years. People are not automatically converting their dissatisfaction with the status quo into support for Romney in the numbers he needs. What’s more, Obama is crushing Romney on who will look out for the middle class, 53-34. And in a very bad finding for Romney, 57 percent say the economy is recovering.

Romney will indict Obama’s economic record tonight, just as his new ad does. And no doubt he’ll score direct hits. But people already know the economy sucks. And they have nonetheless decided that we’re at least on track to recovery. Romney needs to persuade voters that his ideas and policies would make the country recover faster than Obama’s are, and that he would look out for the middle class’s interests in the process. This is precisely what that one sentence in Romney’s ad promises. If he can’t persuade people that one sentence is true, he’ll likely lose the race.

Romney advisers claim that tonight we will see the Romney who cares about putting middle class Americans back to work. But beyond whether Romney “cares,” what will really matter is whether Romney makes a specific and compelling case that his plan would actually accomplish that goal. Sure, other issues will matter, too, such as health care, entitlement reform, taxes, and the deficit. But on the economy — the single most important campaign issue — this is the way to judge his performance. Anything else will likely be just noise.

* Two new polls show tighter race: The NBC/WSJ poll also finds Obama leading nationally among registered voters by 50-47 — tighter than the the five point spread the poll showed two weeks ago. Meanwhile, the new National Journal poll shows the race tied, at 47 apiece. In both polls, the spread is wider (51-44) and 50-44) among registered voters. The NJ poll is a bit out of sync with many recent ones showing Obama at 50 or 49 percent.

Meanwhile, the new NPR poll shows Obama with a bigger lead nationally among likely voters, 51-44. Nate Silver suggests we should watch to see if any national tightening shows up in state polls as a good gauge of what’s really going on.

* Obama leading in Ohio, closer in Florida and Virginia: The new NBC/WSJ state polls show Obama with an eight point lead among likely voters in Ohio, 51-43, relatively unchanged from a week ago. The race has tightened in Florida (47-46) and in Virginia (48-46). Get this: 51 percent in Ohio view Romney negatively.

The lack of movement in Ohio is ominous for Romney. Dems have invested heavily in ads there highlighting his Bain past, refusal to release tax returns, and comments about the freeloading 47 percent; they believe Romney’s pedigree and profile are exactly the wrong fit for the state, given its high concentration of blue collar whites. Also: The auto bailout.

* Obama outgunning Romney on the air: A must read from Jeff Zeleny and Jim Rutenberg detailing a surprising twist in this race: Obama is now outspending Romney and his allies on the air, and the Obama team appears to be strategically outworking the opposition in terms of shrewd ad placement and targeting.

The Romney camp is expected to increase spending in the final few weeks. But the pressure is on the trailing candidate to make gains with advertising, which may be hard given the diminishing returns effect that may kick in with the unprecedented crush of spending.

* Keep an eye on the September jobs report: Reuters:

Companies added 162,000 jobs in September, more than economists expected but still pointing to slow improvement in the labor market, data from a payrolls processor showed on Wednesday.

Of course, this is not the Bureau of Labor Statistics report, which is due out on Friday. If the BLS report shows a weak but positive number, that continues to indicate a weak recovery, which will mean the basic dynamics of the race remain unchanged.

* How about pressing Romney for tax specifics? Kevin Drum suggests a good line of questioning for Romney at tonight’s debates, in light of Paul Ryan’s suggestion yesterday that some middle class tax deductions are off the table: Maybe he can finally tell us how he will cut taxes on everybody, including disproportionately huge cuts for the rich, without exploding the deficit?

David Atkins lays out the real Romney game plan on taxes: “they’ll just do what Republicans always do: cut taxes, balloon the deficit, and then whine and scream about the deficit when a Democrat takes office so that the Democrat will make the ‘starve the beast’ cuts for them.”

* Dems set expectations for the debate: The Obama campaign is out with a new memo that tries to pre-frame the debate on the most favorable terms for itself, arguing that Americans will judge the winner based on who lays out the clearest plan for the country. This is in keeping with the Dem imperative of turning this election into a choice over the future.

* Tight race in Colorado: Scott Conroy has a good report from Colorado, where the race is tighter than expected and Romney strategists insist the Denver suburbs are starting to break their way. Dems had thought the west would be key to offsetting expected Obama losses in the Rust Belt. But now Ohio may be in Obama’s pocket while Colorado has become key for Romney to offset losses. Romney’s historically bad standing among Latinos could loom large for his overall chances.

* And the Drudge video — shock! — turns out to be a bust: I wasn’t even going to get into this, because the whole thing is so ridiculous, but Steve Benen has all you need to know about the idiocy behind the racial video the right got so worked up about yesterday.

As David Kurtz put it: “Breaking: Obama is black.”

What else?