Now that Sarah Palin has given artificial respiration to the John McCain effort by exceeding extremely low expectations in her debate with Joe Biden, it's up to McCain himself to breathe new life into his lethargic campaign.

His next chance comes tomorrow night against Barack Obama at Belmont University in Nashville. That scheduling doesn't allow much time for whatever benefit the Republican ticket may have drawn from perky Palin's stylistic if not substantive success in St. Louis.

Her winking, blinking and nodding performance obviously warmed conservative hearts, and relieved other Republicans fearful that she might have been a standing disaster. But survival is not winning, and the consensus of public-opinion polls rated Biden the more effective debater.

Before and after the debate between the running mates, the issue of qualification to succeed to the presidency hung over the 90-minute exchange. Palin showed she could function quite well as vice president, whose duties are minimal.

As for being president if fate were to so dictate, little she said conveyed the kind of commanding grasp of national and international issues demanded by the job. Miss Congeniality, yes; Madame President, no. It will be interesting to see now whether, in the wake of her debate showing, she will be unleashed to face more open questioning from the news media at large.

In any event, with the election now only a month away, the spotlight swings back to the main event between McCain and Obama. The continuing economic morass is not congenial to the Republican nominee, for all his and Palin's efforts to separate themselves from the GOP administration under which it has deepened.

One of the more notable aspects of Palin's debate performance was the vehemence with which she tossed President Bush over the side, referring to administration "blunders," including conduct of the war in Iraq, which both McCain and Palin say is on a path to "victory."

In her repeated self-identification of themselves as "mavericks," the linchpin of their campaign pitch, Palin labored mightily to counter the central Obama-Biden argument that McCain's election would constitute a Bush third term.

As Biden insisted that McCain's foreign-policy positions on Iraq, Afghanistan, Iran and Pakistan were no different from those of Bush, Palin brushed the comparison aside, complaining of "too much finger-pointing backwards" for a campaign that talked about change.

But Palin contradicted herself by saying she and McCain would look back at Bush's failures themselves in crafting "positive" change. "We'll learn from the past mistakes in this administration and other administrations," she said, continuing to hijack the "change" mantra of the Obama campaign.

While Palin's debate performance was providing a morale boost for the McCain effort, discouraging word was coming from its on-the-ground campaign in the key state of Michigan. Aides said money and other resources were being pulled out, thus conceding the state's 17 electoral votes to Obama.

In the nation's prime auto-making center, particularly hard hit by job losses in the economic crisis, a poll for the Detroit Free Press had Obama with a lead of 51 percent to 38 percent over McCain. Other polls elsewhere had Obama widening his lead in another target state, Virginia, which has not gone Democratic in a presidential race since Lyndon Johnson won there in 1964.

Such trends make clear that the burden of applying the brakes must now fall on McCain himself after a period of erratic maneuverings capped by his off-again, on-again suspension of campaigning to intervene in the congressional bailout fiasco.

After Tuesday night's debate against Obama in Nashville, McCain will have only one more debate, at Hofstra University on Long Island eight days later, to turn around what has become a discouraging outlook in the electoral-vote competition.

The well-heeled Obama campaign, free of spending restrictions by virtue of turning down the federal campaign subsidy, continues to press that advantage in battleground states won by Bush in 2000 and 2004. Some latest Obama television ads have conveyed a softer, positive tone, while McCain's ads are striking a more negative tone, reflecting an awareness of the uphill challenge he now faces.

Jules Witcover's latest book, on the Nixon-Agnew relationship, "Very Strange Bedfellows," has just been published by Public Affairs Press. Reach him at juleswitcover@earthlink.net.