Before tonight's debate even started, Americans received yet another negative headline about the country's economy, as the Dow Jones industrials ended the day down 733 points -- the second-largest drop ever. The economy is clearly the top issue on voters' minds, and recent polls show that more voters trust Barack Obama to handle the financial crisis than John McCain. With 19 days left until the election, McCain's performance tonight likely did little to change that.

McCain delivered some good lines, finally brought up Obama's relationship with former Weather Underground member Bill Ayers and appeared as though a fire had finally been lit inside him. Republicans have practically been begging for that enthusiasm and vigor that, before tonight, they've mostly gotten from McCain's running mate. But, as NBC's Tom Brokaw said moments after the debate ended, "It seems unlikely that anything we heard tonight really moved the needle."

It's tempting to call McCain's performance tonight his finest of the three debates. The format even seemed to benefit him more than it did Obama. The semi-town hall debate in Nashville, Tenn., last week was supposed to be McCain's chance to shine, but he seemed far more comfortable seated at a table. And Obama seemed just the opposite. He looked Obama in the eye when arguing with him and came across as the feisty gentleman many Americans have grown to like over the years.

However, it's not clear that McCain did much to win over the independent and undecided voters whom he vitally needs in order to climb back in the polls and, of course, win when the voting counts on Nov. 4. In a CBS News poll of uncommitted voters taken following the debate, 53 percent said Obama won the debate compared to just 22 percent who felt McCain had (and 24 percent saw it as a draw).

Speaking with Geraldine Ferraro on the Fox News Channel just before the debate, Bill O'Reilly said McCain should not try to "out-policy" Obama because he can't do it. And he didn't. McCain was at his best when discussing topics in general terms: cut taxes, cut spending, free trade, and the two-dozen or so times when he mentioned "Joe the Plumber."

"Why do you want to raise taxes on anyone right now?" McCain asked Obama early on in the debate. "Why do we always have to spend more?" McCain asked later. His best line of the night was one he should have used long ago. "Senator Obama, I am not President Bush. If you want to run against President Bush, you should've run four years ago."

Obama appeared rattled at times when McCain really revved up the attacks, but he delivered his fair share of comeback lines as well. "If I occasionally mistaken your policies for George Bush's policies, it's because on the core economic issues that matter to the American people -- on tax policy, on energy policy, on spending priorities -- you have been a vigorous supporter of President Bush."

Obama's best line of the night was probably this one: "The notion that I voted for a tax increase for people making $42,000 a year has been disputed by everybody. Even Fox News disputes it." That one even drew a chuckle from McCain.

When the debate moved back to specific issues like health care and education, Obama delivered far more coherent arguments for his plans and seemed better able to reach out to voters across the political spectrum. Even when discussing abortion and Roe v. Wade -- a topic that so far has been mostly absent from this campaign -- Obama quickly found a place where both sides of the volatile argument could agree.

This third and final debate tonight between the nominees was probably the liveliest and most entertaining to watch. The candidates finally engaged, leading to some great camera shots of them reacting to each other. There was McCain raising his eyebrows, rolling his eyes and appearing absolutely enraged by things Obama was saying. And Obama, attempting to keep his cool, calm profile as he sipped his water.

McCain was seeking something tonight that could alter the trends of national and battleground state polling. I don't think he got that. He did, however, give a performance that leaves Republicans wondering why he couldn't have done this weeks ago.