In the crowded field of Republican presidential contenders, perhaps no one is better known than Senator John McCain of Arizona. McCain is making his second run for the White House in 2008, and VOA National Correspondent Jim Malone has a profile from Washington.

John McCain was born in the Panama Canal Zone in 1936.

As the son and grandson of U.S. Navy admirals, McCain's military career took him to the Naval Academy, and then into combat as a Navy pilot during the Vietnam War.

After his plane was shot down over North Vietnam in 1967, McCain spent five and a half years as a prisoner of war, endured brutal beatings and came home a national hero.

McCain says his war experience makes him uniquely qualified to be president.

"I can hit the ground running. I do not need any on the job training," he said. I have seen the face of evil. I know the face of war. That will be the issue. That is why I will be President of the United States."

In his four terms as a senator, McCain has earned a reputation as a hawk on foreign policy and defense matters, but as a political maverick on domestic issues.

In 2000, McCain lost his bid for the Republican Party's presidential nomination to then Texas Governor George W. Bush.

McCain hopes to appeal to both conservative and independent voters in his second try for the White House in 2008, with an emphasis on national security.

"Do not tell me we cannot make our country stronger and the world safer. We can. We must," he said. "And when I am president, we will."

The Arizona senator was a driving force behind a campaign finance reform bill and supports legalizing illegal immigrants already in the country.

Both stands have hurt him with conservative Republicans.

Larry Sabato directs the Center for Politics at the University of Virginia.

"Everything from his position on campaign finance reform, immigration, his running against President Bush in the 2000 primaries, which caused great angst and division in many of the places in the Republican Party that you have to do well in to win," he noted.

At one time, McCain was considered the frontrunner among Republican presidential contenders. But his campaign faltered during much of 2007 and he trails rivals like former New York City Mayor Rudy Giuliani and former Senator Fred Thompson of Tennessee.

Among all the Republican candidates, McCain has been the most vocal in support of President Bush's military surge strategy in Iraq.

"The war is far more important than any political ambition that I have," he said. "I believe that if we fail, there will be chaos and genocide in the region and that they will follow us home."

Experts note that during his career McCain has always relished the role of a political underdog.

John Fortier is with the American Enterprise Institute.

"Can he come back? He still does fairly well in the polls. He is a dynamic figure," noted Fortier. "The Republican race is uncertain, so I would not rule him out."

At 71-years-old, McCain would be the oldest person to assume the presidency should he win the 2008 election, surpassing his political hero, Ronald Reagan, who was inaugurated at the age of 69.