John McCain headed into the last 60 days of the US presidential campaign neck and neck with Barack Obama after a “Sarah Palin bounce” appeared to have all but cancelled out the Democrat’s lead in the polls.

With the Republican Party finishing its convention in St Paul believing that victory on November 4 is truly within its grasp, the Rasmussen tracking poll yesterday had Mr Obama on 46 per cent and Mr McCain on 45 per cent.

Mr Obama headed to the battleground state of Pennsylvania last night knowing that he has a titanic fight on his hands to realise his dream of becoming America’s first black president. His aides have said for months that the race for the White House will be close, but Republicans left their Minnesota convention knowing that the contest is now really up for grabs.

The Rasmussen poll, a three-day rolling average, was taken before Mr McCain addressed his party — and many interviews were conducted even before Mrs Palin’s barnstorming performance as “a pitbull with lipstick”, suggesting that there may be further Republican gains in the next few days.

By most measures, the Democratic senator should be well ahead of his rival. The Republicans are facing their worst political circumstances in a generation, with a corrosive party brand, a faltering economy, an unpopular war and a record number of Americans believing that the country is on the wrong track.

Yet Mr McCain remains locked in a tight contest, with Democratic strategists nervous that Mr Obama’s ratings are artificially inflated because of a reluctance among some voters to admit that they are ambivalent about his race. The Democrats’ greatest battle remains in convincing voters to overcome doubts about their man’s background and lack of experience.

In his acceptance speech on Thursday night, Mr McCain, dwelt heavily on his years as a prisoner in Vietnam and the torture that he suffered. “Let there be no doubts, my friends, we’re going to win this election,” he said. “I don’t mind a good fight. For reasons known only to God, I’ve had quite a few tough ones in my life.”

He sought to recast himself as a maverick reformer ready to end the partisan gridlock in Washington: “I will reach out my hand to anyone to help me get this country moving again. I have the record and the scars to prove it. Senator Obama does not.”

Yet the greatest ovations that Mr McCain received came when he praised Mrs Palin, who was again roared on by the crowd as she watched the speech with her husband and five children. The 44-year-old Alaska Governor’s performance on Wednesday — and the melodrama surrounding her family and pregnant teenage daughter — has shaken up the election campaign like no vice-presidential choice in recent times.

She has rallied the Republican base, with aides believing that her personal story will attract a significant number of female swing voters. She also threatens to overshadow Mr McCain and has, for now, succeeded in virtually knocking Mr Obama off the political radar.

Mr McCain and his aides are aware, however, that they still face an uphill struggle. Mr Obama has an edge in most of the battle-ground states and there is a danger that Mrs Palin’s conservative views could yet alienate many swing voters.

Nevertheless, few had heard of her eight days ago and yet a poll yesterday showed her more popular nationally than Mr Obama, Mr McCain or Joe Biden, the Democratic running-mate, with a favourability rating of 58 per cent.

With only two months until the election, Mr McCain and Mr Obama will spend this weekend in the crucial swing states of Michigan and Pennsylvania as they battle for the white, middle-class voters in America’s struggling industrial heartland who will play a significant role in deciding the outcome of this race.

They take to the stump with sobering new unemployment figures dominating the day’s campaigning, a stark reminder of how fear of a recession is the No 1 issue for US voters.

Times Recommends

• Please help: maimed children of war want their lives back
• Cabal seizes diamond riches to buy power
• White House gatecrashers got to the president