The introduction of Sarah Palin as a running mate and a week of sustained attacks on Barack Obama from the Republican National Convention have helped John McCain draw level in the latest opinion polls.
National surveys published over the weekend show the pair in a statistical dead heat, setting up a frenzied final 60 days of campaigning and pinning more importance than ever to the series of candidates' debates.
Against a backdrop of the largest government bail-out of the US housing market since the Great Depression, Senators McCain and Obama were on the stump talking about the economy yesterday, but political attention remained focused on the extraordinary turnaround in Republican fortunes since the nomination of Mrs Palin to the vice-presidency.
As well as energising the Christian right, which had been sceptical about Mr McCain, the choice of the Alaska Governor has shaken up the race for middle America, and for suburban women in particular, who will be critical in swing states such as Ohio and Michigan which could tip the election.
But the Republicans are in no hurry to put their new star in front of questioning journalists. She has been shielded from the media since being picked and will begin giving interviews in a "few days", Mr McCain said yesterday.
While the other contenders have faced more than a year of intense scrutiny, Governor Palin is a newcomer to the national scene. "Eventually, she is going to have to answer questions and not be sequestered," her Democratic counterpart, Senator Joe Biden of Delaware, told NBC.
But Mr McCain's campaign manager, Rick Davis, refused to confirm when the press will get to talk to the woman being credited with changing the race. "She'll agree to an interview when we think it's time and when she feels comfortable doing it," he told Fox News.
Lydia Saad of the pollster Gallup said: "Barack Obama's advantage over John McCain has been shrinking since the start of the Republican National Convention." By last night it had disappeared altogether with Gallup's rolling three-day survey showing Mr McCain three points ahead of his rival on 48 percent.
In the days after Barack Obama's acceptance speech in Denver, Gallup had shown the Democrat candidate briefly touching 50 per cent. That has since slipped to 45 percent.
John Zogby found Mr McCain had surged into the lead in his survey, which puts the Republican candidate on 49 per cent, to Mr Obama's 46 per cent. "Clearly, Palin is helping the McCain ticket," Mr Zogby said. "She has high favourability numbers, and has unified the Republican Party."
Mr Obama continues to have a solid lead in analyses that measure likely electoral college votes, since local polls put him ahead in states with large numbers of electoral college votes. Republican strategists told Mr McCain that he had a mountain to climb and needed to shake up the race with a bold vice-presidential pick; it appears that he has at least started to climb.
Mrs Palin has emerged as a formidable campaigning force, and Mr McCain is planning to stay out on the stump with her for part of the coming week. In a reversal, their appearances this weekend drew crowds of thousands, while Mr Obama has been touring smaller venues.
A rattled Mr Obama trained his fire on Mrs Palin for the first time at a rally in Indiana, referring to reports that she accepted Federal money, known as "earmarks", for Alaska. "When you've been taking all these earmarks when it's convenient, and then suddenly you're the champion anti-earmark person, that's not change," the Illinois senator said.
In a television interview yesterday morning, Mr McCain played up his maverick image, highlighting the issues on which he has broken with the Republican party in the past, and tried to neutralise Democratic complaints that he has sold out many centrist positions to win the presidential nomination.
The Arizona senator also promised to have multiple Democrats in his cabinet, saying he wanted the "best people". He added: "Some of them I'll ask them to work for a dollar a year. They made enough money."