WASHINGTON — In the two weeks the Wall Street financial crisis has dominated the political debate, the presidential race has shifted from what had been essentially a dead heat to one in which Democratic Sen. Barack Obama has opened up a narrow but perceptible advantage nationally, as well as in a number of key battleground states.

The burden now falls on Republican Sen. John McCain to reverse the effects of the focus on the economy and keep the contest close enough so that a dominant debate performance, a gaffe by Obama, or some outside event can shift the momentum back to him.

Although Friday's debate in Oxford, Miss., produced no outright winner, strategists in both parties said the coming weeks, which will include three more debates — two between McCain and Obama and the third between vice presidential candidates Gov. Sarah Palin and Sen. Joseph Biden — could be decisive in determining whether the election remains on a trajectory favorable to Obama or shifts back toward too-close-to-call status.

McCain advisers are well aware that the past two weeks have brought a shift in the race, but they say that between now and Election Day, there is plenty of time for the fortunes of the two candidates to change again.

"The first lesson of this campaign, going back to 2007, is not to be panicky or reactive to poll numbers," said McCain senior adviser Steve Schmidt. "A few weeks back, we had a clear lead, albeit a narrow one, and there were a lot of people on the Democratic side haranguing the Obama campaign in the sense of panic. We always understood not only would that lead dissipate but bounce back the other way and then bounce back again."

UNDECIDEDS CRUCIAL

For McCain, the danger is that previously undecided voters will become comfortable that Obama is ready to be president. The longer Obama can hold even a small lead, the more difficult it will be for McCain to reverse it, absent something unexpected happening. McCain's best hope, strategists said, is for the crisis atmosphere around Wall Street and the credit markets to lessen, allowing the campaign debate to focus on other questions as much as the economy.

Schmidt said the campaign will press two arguments as forcefully as possible in the coming days. One is that Obama is not ready to be commander in chief and that, in a time of two wars, "his policies will make the world more dangerous and America less secure." Second, he said, McCain will argue that, in a time of economic crisis, Obama will raise taxes and spending and "will make our economy worse."

Obama signaled yesterday that his focus will be on painting McCain as out of touch on the economy. At a rally in Greensboro, N.C., Obama ripped into his rival's remarks about the economy during the debate — but more for what McCain didn't say.

"The truth is, through 90 minutes of debating, John McCain had a lot to say about me, but he had nothing to say about you. He didn't even say the words 'middle class.' Didn't say the words 'working people,' " Obama told a cheering crowd of about 20,000 people yesterday. He later appeared in Fredericksburg, Va., and was scheduled to speak at the Congressional Black Caucus dinner in Washington.

McCain, who returned to Washington immediately after the debate, remained largely out of sight yesterday. Aides said he was working the phones with congressional leaders, monitoring the pace of negotiations over a financial rescue package that officials hope to have ready for a vote by the beginning of the week. They argued that without his input, the package under consideration earlier last week was doomed to fail.

But strategists said McCain will be challenged to reverse current trends, particularly in a year in which voters are gloomy about the state of the country and are looking for a change in direction after eight years of President Bush's policies.

"What begins to happen is that the margin that's been in place begins to solidify more and more," said Matthew Dowd, who was Bush's chief strategist in 2004 and now is an independent analyst. "There's only two ways this can go," he added. "It will either solidify with an Obama four- to five-point lead, or it will loosen and go back to close and go back and forth."

PALIN'S STRUGGLES

Obama and McCain will not debate again until Oct. 7, but Palin and Biden will meet in St. Louis on Thursday for their only debate. Palin had an immediate and positive effect on the race when she was chosen, but that has dissipated over the past two weeks. She struggled through an interview with CBS anchor Katie Couric last week, and polls show rising unfavorable ratings, including among independent female voters. As a result, Palin faces a major test against the more experienced Biden in the debate.

The second presidential debate will have a town hall format, which makes combat between the two candidates more difficult. If the race stands essentially as it does today by the time of the third debate on Oct. 15, strategists predict a fierce and confrontational 90 minutes. By then it will become clear whether McCain made the right decision politically to suspend most campaign activities last week and return to Washington to get involved in the financial package negotiations. Aides hope that, if Congress passes a rescue package, McCain's actions will be seen as having contributed to the deal. More important, they hope an agreement will push the economy story off the front pages for a time.

Their hope is to keep things fluid for the next few weeks.

"You've got to get it over with and start having a normal campaign," said one McCain adviser.