Vietnam veteran John McCain declared on Thursday he was ready to fight for his country once more, but this time from the corridors of power rather than on bloody battlefields.

"I don't mind a good fight. For reasons known only to God, I've had quite a few tough ones in my life," McCain (72) told Republicans as he proudly accepted the mantle as the party's standard-bearer in the November presidential elections.

"But I learned an important lesson along the way. In the end, it matters less that you can fight. What you fight for is the real test."

Put Obama on notice

And he put his Democratic rival Barack Obama on notice that this fight was personal, forged by his horrific experiences as a prisoner-of-war in Vietnam after being shot down in October 1967.

"I'm not running for president because I think I'm blessed with such personal greatness that history has anointed me to save our country in its hour of need," McCain said in a sly aside to Obama's growing cult status.

"My country saved me. My country saved me, and I cannot forget it. And I will fight for her for as long as I draw breath, so help me God."

His acclamation by a huge crowd packed into the 20 000-seat Xcel centre in St Paul, Minnesota, marked a crowning moment for a man who has spent a lifetime working for his country.

Reputation as a maverick

During more than two decades in Congress since winning his first seat in 1982, McCain has earned the respect of fellow lawmakers on both sides of the aisle for his crusade against corruption, cronyism and wasteful spending.

But the Arizona senator's candor and his willingness to cut across party lines to get things done also earned him a reputation as a maverick, leaving some in his own party wary of just what he would do next.

It's a reputation he revels in, but it was his compelling life story which he focused on during his Thursday speech to the party convention as he sought to convince voters that it made him the best man to be commander-in-chief.

"In Vietnam, where I formed the closest friendships of my life, some of those friends never came home with me. I hate war. It is terrible beyond imagination," he said.

"I'm running for president to keep the country I love safe, and prevent other families from risking their loved ones in war as my family has.

"I will draw on all my experience with the world and its leaders, and all the tools at our disposal — diplomatic, economic, military and the power of our ideals — to build the foundations for a stable and enduring peace."

Larger than life

McCain is a larger-than-life character who has more than once defied the odds.

Living up to his image as a man who works on gut-feeling and often shoots from the hip, he threw a bombshell into the 2008 White House race last week by picking Sarah Palin, the little-known governor of Alaska for his running-mate.

Since then she has wowed the Republican grassroots base, despite a string of personal revelations, but it remains to be seen whether she can woo women voters over to McCain's side.

John Sidney McCain was born on 29 August 1936 in the Panama Canal Zone — formerly under US jurisdiction — and was raised in the tradition of US military "brats" moving from post to post.

Both his grandfather and father were naval officers, so it was no surprise when at 17 he enrolled in the naval academy.

Angered conservatives

While his campaign says his credentials — as a military man and a veteran — to be the country's wartime commander-in-chief are impeccable, conservatives have been angered by his positions on fiscal reform and immigration.

He is opposed to any use of torture by the United States in its "war on terror." But in many other areas, he remains a dyed-in-the-wool conservative, opposing abortion, gay marriage and stricter gun control laws.

His first wife, Carol, was disabled in a car accident and McCain admits that his "wandering" led to their divorce.

McCain re-married in 1980 to Cindy, a wealthy Arizona beer heiress. He has seven children from the two marriages, of which three are adopted.

If elected in Novmber, McCain would be the oldest person ever elected for a first term to the White House. And although doctors have pronounced him as fit, he has also survived a brush with skin cancer.

AFP