When George “Bud” Day first set eyes on John McCain in a Vietnamese prisoner of war camp, he doubted his new cell-mate would survive until the following morning, let alone return to America to become a senator and eventually a presidential candidate.

“He was emaciated and puny and although he was a young man his hair had turned white,” Day recalled last week. “He had obviously been starved. I was positive he’d die.”

Day was in no great shape himself. A US air force pilot, he had been shot down over Vietnam in August 1967 and badly injured when ejected from his plane. He was captured, then escaped, was caught again but refused to surrender. The Vietnamese shot him and later bayoneted his left leg to discourage further escapes.

Yet somehow, against overwhelming odds, the two cell-mates survived monstrous torture, nursed each other through agonising injuries and forged a lifelong friendship that added an intriguing twist last week to the 2008 presidential campaign.

While McCain’s experiences as a captured navy pilot during the Vietnam war are scarcely a secret, the Republican candidate rarely discusses in public the details of his wartime captivity. Nor does he ever talk about the military service of his son, a US marine who has fought in Iraq.

McCain’s reticence, born of both a natural modesty and a fierce determination to protect his family’s private life, has begun to worry prominent Republican strategists, who believe the endless Democratic feuding between Hillary Clinton and Barack Obama has opened the White House door to McCain – provided he opens up his own life to the kind of intimate scrutiny that presidential voters have come to expect.

Those worries were aired last week in a striking commentary by Karl Rove, President George W Bush’s former campaign manager, who has often been accused of masterminding the vicious campaign of character assassination that knocked McCain out of the 2000 presidential race.

Whatever Rove thought of McCain eight years ago – when anonymous Bush supporters falsely accused the Arizona senator of fathering an illegitimate black child, and of being mentally unbalanced from the stress of his Vietnamese torture – the adviser who became known as “Bush’s brain” is now going out of his way to praise McCain’s “character, integrity and essential decency”.

Indeed, Rove went all the way to Florida, where he had dinner with Day and his wife Doris. Whatever his intentions, there was no doubting the value of the story he uncovered.

From the moment he was forced to bale out, Day was determined to escape his captors and return to flying duties. His repeated acts of selfless bravery later earned him the Congressional Medal of Honour, America’s highest award for valour.

When Day’s Vietnamese captors realised he was an incorrigible escaper driven by his dream of flying, they broke his arm so badly the bone was pressing against his skin. They then encased it in a misshapen cast so it would heal deformed, preventing him from ever flying again.

“John and I got talking about what to do,” Day said last week. “He said, ‘Well, I’ll see if I can pull it back together’.”

In the filthy confines of their cramped cell, risking further punishment from their guards, the two men embarked on an excruciating experiment in bone repair. “John basically put his foot in my armpit and pulled,” Day said.

With no formal medical training, McCain somehow managed to wrench the bone back into place. The two men fashioned a makeshift splint from strips of bamboo found in the yard. “It healed, really quite soon,” Day said. He would fly again.

Day has many other stories of unimaginable stress and stirring comradeship. The point, Rove argued, was that these were stories Americans should hear. “I have heard things about Senator McCain that were deeply moving and politically troubling,” he said. “Troubling because it is clear that Mr McCain is one of the most private individuals to run for president in history.” American voters “want to know more about a candidate than policy positions”, he continued.

McCain’s aides have been politely keeping their distance from Rove, who is seen by some to be either looking for a job in a McCain administration or, at the very least, trying to ensure that he would not be shunned by a new Republican White House.

Last week Day, who is still sprightly at 83, was happy to oblige with tales of derring-do from the Hanoi Hilton and other prison camps. “John has always felt on all kinds of issues a strong determination to do things on his own terms,” Day said. “That got him through Vietnam and I don’t think it will change. His son Jim saw combat in Iraq, but he has always refused to use his children in his campaign. Personally, I find that admirable.”

To Rove, the calculating strategist, it may be admirable but it makes no political sense. “Candidates who are uncomfortable sharing their interior lives limit their appeal,” he warned.

Footage of McCain as POW

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