ST. LOUIS — On the night after the U.S. Senate endorsed a $700 billion plan to bail out collapsing banks, and on the day before the U.S. House will be asked to do the same, the economy was going to be the central issue of the first and only vice presidential debate.

Neither Sarah Palin nor Joe Biden wanted to be on the wrong side of the divide between what a previous vice presidential contender famously — and accurately — described as “two Americas.”

So it was the chairman of the Senate Foreign Relations Committee and the sitting governor of the nation’s physically-largest state spent the evening talking about buying gas “with a guy named Joe” and rallying “Joe Six Packs (and) hockey moms across the nation.”

Biden and Palin both buffed their blue-collar credentials. They told stories of personal woe. Biden referenced tough times on streets of Scranton and Wilmington. Palin recalled going without health-care coverage. Biden’s voice caught as he spoke of caring as a single parent for an injured child.

For the most part, however, the candidates eschewed personality profiling in favor of full-throated denunciations of all things Wall Street.

“If you need any more proof positive of how bad the economic theories have been, this excessive deregulation, the failure to oversee what was going on, letting Wall Street run wild, I don’t think you needed any more evidence than what you see now,” griped Biden.

“Darn right it was the predator lenders, who tried to talk Americans into thinking that it was smart to buy a $300,000 house if we could only afford a $100,000 house. There was deception there, and there was greed and there is corruption on Wall Street. And we need to stop that,” grumbled Palin.

If they walked the same stylistic line when it came to trying to out-populist one another, however, the candidates divided on the issues.

And that is how Biden prevailed.

Let’s be clear that Palin did not crash and burn as her most ardent detractors anticipated – or, at the least, hoped – she would. Yes, the governor rambled at times, and she had no comebacks at those moments when Biden directly challenged the validity of her over-the-top claims about Democratic presidential nominee Barack Obama’s Senate voting record. But Palin gave Republican spin doctors enough material – mainly in the form of folksy one-liners — so that they could cheer her “success” without sounding entirely ridiculous.

The anticipated gravitas gap was on display, especially when the senior senator’s encyclopedic knowledge of foreign and domestic policy – and of Republican presidential nominee John McCain’s voting record – was contrasted with Palin’s encyclopedic knowledge of tax codes in Wasilla, her desperate clinging to the word “maverick” and her line-of-the-night observation that unleashing “nuclear weaponry, of course, would be the be-all, end-all of just too many people and too many parts of our planet.”

But Palin was not the moose-in-the-headlights that America saw talking with CBS News anchor Katie Couric. She was generally on message, and the message was “us-against-them” populism.

Asked by moderator Gwen Ifill about the condition of the economy, Palin responded, “You know, I think a good barometer here, as we try to figure out has this been a good time or a bad time in America’s economy, is go to a kid’s soccer game on Saturday, and turn to any parent there on the sideline and ask them, ‘How are you feeling about the economy?’ And I’ll bet you, you’re going to hear some fear in that parent’s voice, fear regarding the few investments that some of us have in the stock market. Did we just take a major hit with those investments?”

That was suitably “of the people” – especially coming from a rather wealthy suburban Republican.

Unfortunately for Palin, Biden recognized an opening, and he took it.

“(It) was two Mondays ago (that) John McCain said at 9 o’clock in the morning that the fundamentals of the economy were strong. Two weeks before that, he said… we’ve made great economic progress under George Bush’s policies,” the senator began. “Nine o’clock, the economy was strong. Eleven o’clock that same day, two Mondays ago, John McCain said that we have an economic crisis. That doesn’t make John McCain a bad guy, but it does point out he’s out of touch. Those folks on the sidelines knew that two months ago.”

Again and again, when Palin went populist, Biden went after McCain.

Take the point at which Palin was ready to lead the rabble to the barricades.

“(Let’s commit ourselves just every day American people, Joe Six Pack, hockey moms across the nation, I think we need to band together and say never again,” she announced. “Never will we be exploited and taken advantage of again by those who are managing our money and loaning us these dollars. We need to make sure that we demand from the federal government strict oversight of those entities in charge of our investments and our saving…”

Biden did not ridicule his opponent’s pretense.

Rather, he suggested that, while Palin could talk all she liked about rallying the masses against Wall Street, she would have a hard time getting John McCain on board for the revolution.

“Two years ago, Barack Obama warned about the sub-prime mortgage crisis. John McCain said shortly after that in December he was surprised there was a sub-prime mortgage problem. John McCain, while Barack Obama was warning about what we had to do, was literally giving an interview to The Wall Street Journal saying that ‘I’m always for cutting regulations.’ We let Wall Street run wild. John McCain and he’s a good man, but John McCain thought the answer is that tried and true Republican response: deregulate, deregulate,” Biden told Palin, and America.

“So what you had is… overwhelming deregulation. You had actually the belief that Wall Street could self-regulate itself. And while Barack Obama was talking about reinstating those regulations, John on 20 different occasions in the previous year and a half called for more deregulation. As a matter of fact, John recently wrote an article in a major magazine saying that he wants to do for the health care industry deregulate it and let the free market move like he did for the banking industry.”

That was an ouch moment.

And it got more painful for Palin when, toward the end of the debate, Biden took the word the Republican clung to so fervently Thursday night – “maverick” – away from her, and from John McCain.

“Let’s talk about the maverick John McCain is. And, again, I love him. He’s been a maverick on some issues, but he has been no maverick on the things that matter to people’s lives,” Biden carefully explained. “He voted four out of five times for George Bush’s budget, which put us a half a trillion dollars in debt this year and over $3 trillion in debt since he’s got there. He has not been a maverick in providing health care for people. He has voted against — he voted including another 3.6 million children in coverage of the existing health care plan, when he voted in the United States Senate. He’s not been a maverick when it comes to education. He has not supported tax cuts and significant changes for people being able to send their kids to college. He’s not been a maverick on the war. He’s not been a maverick on virtually anything that genuinely affects the things that people really talk about around their kitchen table. Can we send — can we get Mom’s MRI? Can we send Mary back to school next semester? We can’t — we can’t make it. How are we going to heat the … house this winter? He voted against even providing for what they call LIHEAP, for assistance to people, with oil prices going through the roof in the winter. So maverick he is not on the important, critical issues that affect people at that kitchen table.”

A Republican named Sarah Palin tried to convince Americans that she was running on a populist ticket.

But Joe Biden reminded the voters sitting at those kitchen tables, in those small houses with big mortgages, that the man who heads that ticket, a Republican named John McCain, is not on their side.

And, in so doing, Biden did not merely score a debating point. He did what a vice presidential candidate is supposed to do. He helped the man who heads his ticket, a Democrat named Barack Obama, stake a significantly stronger claim on the presidency.