Influential Republican senator John McCain surprised few in Washington when he announced late on Wednesday that he would run for the White House in the 2008 presidential race.
McCain, who lost his party's nomination in 2000 to nowPresident George Bush, made the announcement at an unusual venue: CBS television's Late Show with David Letterman - a comedy talks show.
McCain said on the show: "I am announcing that I will be a candidate for president of the US."
He later said that he would make a formal announcement in April.
"You drag this out as long as you can," he said. "You don't just have one rendition."
The outspoken Arizona senator, 70, once a front-runner among Republican faithful, has seen his standing in the polls slip.
A Wednesday survey placed him well behind his main rival, former New York mayor Rudolph Giuliani.
Giuliani scored 44% support, against 34% on January 19, according to the ABC News- Washington Post poll. McCain slipped six points, from 27% in January to 21%.
The senator described Giuliani on CBS as a "genuine American hero" and "a formidable candidate".
McCain has long supported the unpopular Iraq war, arguing that more soldiers were needed to flush out insurgents, crush militias and train Iraqi forces - a position since taken up by the president.
A former navy pilot and Vietnam prisoner of war, McCain even called for more US troops in Iraq following the November elections that saw Republicans lose control of both chambers of congress on voter unhappiness with the war.
He said he would not be anyone's running mate.
"I spent all those years in a North Vietnamese prison camp, kept in the dark, fed scraps - why the heck would I want to do that all over again?" he told Letterman.
In mid-February, McCain travelled to conservative South Carolina and delivered a hawkish speech supporting US efforts in Iraq.
"I can't guarantee success, but I can guarantee the consequences of failure," McCain said. "If we leave Iraq, you would see chaos; you would see genocide.
"And sooner or later we would be back," he said.
At the South Carolina event he took a broadside at one of the main architects of the Iraq war. Former defence secretary Donald Rumsfeld "will go down in history as one of the worst secretaries of defence" for his "mismanagement" of the war, McCain said.
Vice-President Dick Cheney defended his longtime friend Rumsfeld two days later.
"John's entitled to his opinion. I just think he's wrong," Cheney said in an interview with ABC News.
"I think he (Rumsfeld) did a superb job in terms of managing the Pentagon under extraordinarily difficult circumstances."
McCain - who pulled an upset victory in a Republican nomination event early in the 2000 presidential race - was savaged by supporters of then-Texas governor Bush when he reached South Carolina.
Anonymous e-mail messages and fliers began to circulate questioning McCain's conservatism, his patriotism and his personal life, even accusing him of fathering illegitimate children and his wife of being a drug addict.
McCain counterattacked, accusing two powerful evangelical Christian leaders, Jerry Falwell and Pat Robertson, of being "agents of intolerance" and "corrupting influences" in American politics.
A day later, he attacked "the evil influence that they exercise over the Republican Party".
McCain lost the South Carolina primary, and eventually lost the nomination to Bush.