History is likely to conclude that John McCain lost the 2008 presidential race not on polling day, but seven weeks earlier, on the morning that Wall Street was thrown into panic by the collapse of Lehman Brothers.

While the markets were nose-diving, the Republican was telling a rally in Florida that “the fundamentals of the economy are sound”.

It was a reasonable, even responsible, thing to say – reassuring voters that, while the markets were tanking, the economy was not about to disintegrate.

But politically the remark was disastrous. For the next two months Democrats pilloried Mr McCain as out of touch for talking up the economy while people suffered. Before the crisis struck, Mr McCain had opened a narrow opinion poll lead for the first time in months. But Barack Obama regained his advantage as Wall Street reeled and he never again let it slip.

Mr McCain tried to regain the initiative by theatrically suspending his campaign to enter negotiations over the $700bn (£442bn) financial sector bail-out. But his intervention failed to break the deadlock. He ended up looking impulsive and ineffective.

The episode brought longstanding questions about Mr McCain’s temperament to the fore, allowing Democrats to plausibly cast their candidate as the safest choice despite his opponent’s greater experience.

There was one other key moment that helped cost Mr McCain the election but was little noticed at the time. Late last year he gave an interview in which he conceded that “the issue of economics is not something I’ve understood as well as I should”.

It was a candid remark in keeping with his “straight talk” reputation, but it cost him heavily later. Without that admission, there was little reason for voters to view Mr McCain as ill-qualified to handle the economy.

There was even a case to be made that his six years of experience on the Senate commerce committee gave him more economic experience than his opponent.

Instead, the Democrats were able to spend 10 months highlighting Mr McCain’s self-acknowledged ignorance on what became the most important campaign issue.

The remark came when he was still expecting to run a campaign focused on national security – his strongest issue. But progress in Iraq and the decline in US casualties pushed the war off the front pages.

Arguably Mr McCain’s biggest obstacle was his association with George W. Bush, the outgoing Republican president, at a time when polls showed up to 80 per cent of Americans thought the country was heading in the wrong direction.

He also faced a huge financial disadvantage in a year of record fundraising by Mr Obama – a disparity worsened by his opponent’s decision to renege on an earlier commitment to accept spending limits under the public finance system.

The Republican struggled to find a consistent message – at times trying to reignite the poisonous culture wars of the 2004 election, at others attempting to appeal to independents with his “maverick” brand. His high-risk choice of Sarah Palin as running mate backfired.

Critics say Mr McCain was ill-served by Steve Schmidt, his chief strategist, and other Bush-Cheney veterans who encouraged negative attacks.

Mr McCain stuck to his word not to exploit the racially divisive controversy over Jeremiah Wright, Mr Obama’s former pastor, but authorised other smears.

Mark Salter, Mr McCain’s closest aide, says the senator has no regrets. “We fought our way through the most challenging environment in my lifetime. And it was just one damn thing after another ,” he said on the eve of polling. “Win or lose, he ought to be very proud.”

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