It may come to be remembered as the moment when John McCain shed his straight-talking image and became just another message-controlled politician.
By Andrew Ward in Washington
Early this summer, the Arizona senator was holding court with reporters on his “Straight Talk Express” campaign bus when caught off-guard by an awkward question about Viagra.
Did he think it was right that many health insurance policies cover erectile dysfunction medication but not birth control?
Mr McCain squirmed in his seat for what seemed like an eternity before blurting that it was “not something I have thought much about”.
Video of the embarrassing moment was playing on YouTube within hours, reinforcing the early summer narrative of an ageing and out-of-touch candidate struggling to keep pace with Barack Obama.
Since that day, Mr McCain has held only a handful of formal press conferences and abandoned altogether the free-flowing question and answer sessions with reporters that were once his trademark.
His subsequent retreat behind a wall of controlled messages and negative advertising has transformed his relationship with the media from one of the cosiest in US politics into one of mutual hostility.
Like scorned lovers, many in the media have accused him of becoming just the kind of cynical, win-at-all-costs politician he once derided.
Voters appear unconcerned by the change, judging by Mr McCain’s recent surge in the polls, and it may even have helped reassure conservatives who have long been suspicious of his intimacy with the “liberal media”.
Once known as the media’s favourite Republican, Mr McCain has looked eager for confrontation with his former friends in recent weeks, knowing that few things stir greater passion among conservatives than a fight with the Fourth Estate.
He has lashed out against hostile scrutiny of Sarah Palin, his running mate, and goaded reporters over their alleged swooning over Mr Obama, just as his own opponents once complained of favouritism towards him.
Mr McCain’s break with the media coincided with a staff shake-up in July that handed day-to-day control of the campaign to Steve Schmidt, the combative strategist who led “rapid response” operations for the Bush-Cheney campaign in 2004.
Mr Schmidt recognised that Mr McCain’s anything-goes approach to the press had become a liability in the YouTube era and was making it difficult for the campaign to deliver a disciplined message. The senator’s hesitant answer to the Viagra query suggested he recognised it too.
Tighter media control was part of broader changes to the campaign over the summer as its once free-wheeling spirit gave way to a more focused and aggressive atmosphere.
At the heart of the tough new approach has been a series of negative attacks against Mr Obama that have, at the very least, stretched truth to the limit. One advertisement last week accused the Democrat of supporting sex education in kindergarten, based on the flimsy premise that he once backed measures to warn children about sexual predators.
David Plouffe, the Obama campaign manager, accused Mr McCain of “running the most negative and dishonest campaign in modern presidential history”. Even Karl Rove, the famously ruthless former adviser to President George W. Bush, said the McCain campaign had gone too far.
Joe Biden, Mr Obama’s running mate, recalled that Mr McCain was himself the victim of vicious smears by allies of Mr Bush in the 2000 Republican primaries. “Now, some of the very same people and the tactics he once deplored, his campaign now employs,” he said.
Mr McCain has faced a growing media backlash against the negative attacks, with one recent headline accusing him of “a toxic mix of lies and double-speak”.
More sympathetic commentators say the criticism is overblown, arguing that McCain has done nothing to equal the Republican “Swift Boat attacks” against John Kerry in 2004 and has so far refrained from exploiting the racially charged controversy over Jeremiah Wright, Mr Obama’s former pastor.
McCain officials say their opponent has also played fast and loose with facts, including the distorted claim that Mr McCain wants to keep US troops in Iraq for 100 years, while making increasingly explicit attempts to raise concern over the senator’s advanced age.
Mr McCain blames the sour tone on Mr Obama’s rejection of his proposal to campaign together at joint town hall-style meetings. “If we had done what I asked Senator Obama to do, I don’t think you’d see this tenor,” he said.
Media disapproval may prove damaging if it undermines Mr McCain’s reputation as an honourable and principled politician. But a similar outcry against attacks on Mr Kerry in 2004 made little impact and polls show people have greater faith in Mr McCain than in the media.
McCain officials say his aggressive campaign reflects lessons learnt from the 2000 presidential race, when he won the adoration of reporters by playing nice but lost the nomination. This time he is in it to win.