What we learned last week is that the man who always puts his "country first" will take the country down with him if that's what it takes to get to the White House.

For all the focus on Friday night's deadlocked debate, it still can't obscure what preceded it: When John McCain gratuitously parachuted into Washington on Thursday, he didn't care if his grandstanding might precipitate an even deeper economic collapse. All he cared about was whether he might save his campaign. George Bush put more deliberation into invading Iraq than McCain did into his own reckless invasion of the delicate Congressional negotiations on the bailout plan.

By the time he arrived, there already was a bipartisan agreement in principle. It collapsed hours later at the meeting convened by the president in the Cabinet Room. Rather than help try to resuscitate Wall Street's bloodied bulls, McCain was determined to be the bull in Washington's legislative china shop, running around town and playing both sides of his divided party against Congress's middle. Once others eventually forged a path out of the wreckage, he'd inflate, if not outright fictionalize, his own role in cleaning up the mess his mischief helped make. Or so he hoped, until his ignominious retreat.

The question is why would a man who forever advertises his own honor toy so selfishly with our national interest at a time of crisis. I'll leave any physiological explanations to gerontologists - if they can get hold of his complete medical records - and any armchair psychoanalysis to the sundry McCain press acolytes who have sorrowfully tried to rationalize his erratic behavior this year. The other answers, all putting politics first, can be found by examining the 24 hours before he decided to "suspend" campaigning and swoop down on the Capitol to save America from the Sunnis or the Shia, or whoever perpetrated all those credit-default swaps.

To put these 24 hours in context, you must remember that McCain not only knows little about the economy but that he has not previously expressed any urgency about its meltdown. It was on Sept. 15 - the day after his former idol Alan Greenspan pronounced the current crisis a "once-in-a-century" catastrophe - that McCain reaffirmed for the umpteenth time that the "fundamentals of our economy are strong." As recently as Tuesday he had not yet even read the two-and-a-half-page bailout proposal first circulated by Hank Paulson last weekend. "I have not had a chance to see it in writing," he explained. (Maybe he was waiting for it to arrive by Western Union instead of PDF.)

Then came Black Wednesday - not for the stock market, which was holding steady in anticipation of Washington action, but for McCain. As the widely accepted narrative has it, his come-to-Jesus moment arrived that morning, when he awoke to discover that Barack Obama had surged ahead by nine percentage points in the Washington Post/ABC News poll. The McCain campaign hastily suited up its own pollster to belittle that finding - only to be drowned out by a fusillade of new polls from Fox News, Marist and CNN/Time, each with numbers closer to Post/ABC than not. Obama was rising most everywhere except the moose strongholds of Alaska and Montana.

That was not the only bad news raining down on McCain. His camp knew what Katie Couric had in the can from her interview with Sarah Palin. The first excerpt was to be broadcast by CBS that night, and it had to be upstaged fast.

But even that wasn't the top political threat McCain faced last week. Bigger still was the mounting evidence of the seamless synergy between his campaign and Fannie Mae and Freddie Mac, the mortgage monsters at the heart of the housing bust that set off our current calamity. Most of all, it was the fast-moving events on that front that precipitated his panic to roll out his diversionary, over-the-top theatrics on Wednesday.

What we were learning - through The New York Times, Newsweek and Roll Call - was ugly. Davis Manafort, the lobbying firm owned by McCain's campaign manager, Rick Davis, had received $15,000 a month from Freddie Mac from late 2005 until last month. This was in addition to the $30,000 a month that Davis was paid from 2000 to 2005 by the so-called Homeownership Alliance, an advocacy organization that he headed and that was financed by Freddie and Fannie to fight regulation.

The McCain campaign tried to pre-emptively deflect such revelations by reviving the old Rove trick of accusing your opponent of your own biggest failings. It ran attack ads about Obama's own links to the mortgage giants. But neither of the former Freddie-Fannie executives vilified in those ads, Franklin Raines and James Johnson, had worked at those companies lately or are currently associated with the Obama campaign. (Raines never worked for the campaign at all.) By contrast, Davis is the tip of the Freddie-Fannie-McCain iceberg. McCain's senior adviser, his campaign's vice chairman, his Congressional liaison and the reported head of his White House transition team all either made fortunes from recent Freddie-Fannie lobbying or were players in firms that did.

By Wednesday, the McCain campaign's latest tactic for countering this news - attacking the press, especially The Times - was paying diminishing returns. Davis abruptly canceled his scheduled appearance that day at a weekly reporters' lunch sponsored by The Christian Science Monitor, escaping any further questions by pleading that he had to hit the campaign trail. (He turned up at the "21" Club in New York that night, wining and dining McCain fund-raisers.)

It's then that Angry Old Ironsides McCain suddenly emerged to bark that our financial distress was "the greatest crisis we've faced, clearly, since World War II" - even greater than the Russia-Georgia conflict, which in August he had called the "first probably serious crisis internationally since the end of the cold war." Campaigns, debates and no doubt Bristol Palin's nuptials had to be suspended immediately so he could ride to the rescue, with Joe Lieberman as his Robin.

Yet even as he huffed and puffed about being a "leader," McCain took no action and felt no urgency. As his Congressional colleagues worked tirelessly in Washington, he malingered in New York. He checked out the suffering on Main Street (or perhaps High Street) by conferring with Lady Lynn Forester de Rothschild, the Hillary-turned-McCain supporter best known for her fabulous London digs and her diatribes against Obama's elitism. McCain also found time to have a well-publicized chat with one of those celebrities he so disdains, Bono, and to give a self-promoting public speech at the Clinton Global Initiative.

There was no suspension of his campaign. His surrogates and ads remained on television. Huffington Post bloggers, working the phones, couldn't find a single McCain campaign office that had gone on hiatus. This "suspension" ruse was an exact replay of McCain's self-righteous "suspension" of the G.O.P. convention as Hurricane Gustav arrived on Labor Day. "We will put aside our political hats and put on our American hats," he declared then, solemnly pledging that conventioneers would help those in need. But as anyone in the Twin Cities could see, the assembled put on their party hats instead, piling into the lobbyists' bacchanals earlier than scheduled, albeit on the down-low.

Much of the press paid lip service to McCain's new "suspension" as it had to its prototype. In truth, the only campaign activity McCain did drop was a Wednesday evening taping with David Letterman. Don't mess with Dave. Picking up where the "The View" left off in speaking truth to power, the uncharacteristically furious host hammered the absent McCain on and off for 40 minutes, repeatedly observing that the cancellation "didn't smell right."

In a journalistic coup de grâce worthy of "60 Minutes," Letterman went on to unmask his no-show guest as a liar. McCain had phoned himself that afternoon to say he was "getting on a plane immediately" to deal with the grave situation in Washington, Letterman told the audience. Then he showed video of McCain being touched up by a makeup artist while awaiting an interview by Couric that same evening at another CBS studio in New York.

It's not hard to guess why McCain had blown off Letterman for Couric at the last minute. The McCain campaign's high anxiety about the disastrous Couric-Palin sit-down was skyrocketing as advance excerpts flooded the Internet. By offering his own interview to Couric for the same night, McCain hoped (in vain) to dilute Palin's primacy on the "CBS Evening News."

Letterman's most mordant laughs on Wednesday came when he riffed about McCain's campaign "suspension": "Do you suspend your campaign? No, because that makes me think maybe there will be other things down the road, like if he's in the White House, he might just suspend being president. I mean, we've got a guy like that now!"

That's no joke. Bush has so little credibility he can govern only through surrogates (Paulson is the new Petraeus). When he spoke about the economic crisis in prime time earlier that same night, he registered as no more than an irritating speed bump en route to "David Blaine: Dive of Death."

It's that utter power vacuum that gave McCain the opening to pull his potentially catastrophic display of economic "leadership" last week. He may be the first presidential candidate in our history to risk wrecking the country even before being voted into the Oval Office.