Republican John McCain has officially launched his 2008 campaign for president. The Arizona senator is hoping to regain some of the political momentum he has lost in recent months to former New York City Mayor Rudy Giuliani, who leads the Republican presidential field in public-opinion polls. VOA National Correspondent Jim Malone has more from Washington.

John McCain and his wife Cindy in Portsmouth, New Hampshire, 25 Apr 2007

McCain began his second bid for the White House in the early presidential contest state of New Hampshire, the site of his primary victory over then Texas Governor George W. Bush in 2000.

McCain cast himself as the best qualified and most experienced candidate in the presidential field, noting his years of service in Congress and before that in the military, including nearly six years as a prisoner of war in Vietnam.

If elected next year, the 70-year-old McCain would be the oldest first-term president. But McCain sought to turn his age into an asset as he addressed a crowd of supporters in Portsmouth, New Hampshire.

"My friends, we face formidable challenges," said John McCain. "I am not afraid of them. I am prepared for them. I am not the youngest candidate, but I am the most experienced! I know how to fight and I know how to make peace. I know who I am and what I want to do."

McCain is a strong supporter of the war in Iraq and a leading proponent of President Bush's troop surge strategy in an effort to quell sectarian violence.

McCain acknowledged that the Bush administration has made mistakes in Iraq. But the Arizona Republican also pledged to make the overall war on terror a priority if he wins the presidency next year.

"To strengthen our military, intelligence, diplomacy and law enforcement and use the power of American ideals and commerce to win the war against violent extremists and help the majority of Muslims who believe in progress and peace to win the struggle for the soul of Islam," he said.

McCain currently runs second in public opinion polls among Republican candidates, behind former New York City Mayor Rudy Giuliani.

Giuliani has also been campaigning in New Hampshire and told a Republican audience that a Democratic president would go on defense in fighting the war on terror, while a Republican president would remain on offense.

"We are going to win that war whether there is a Republican president or a Democratic president or any other president," said Rudy Giuliani. "The question is going to be, how long does it take and how many losses do we have along the way? And to do that, I believe we are going to be much better off electing a Republican president, and I think we are going to be much better off electing me, and I need your support and your help. Thank you very much."

Giuliani's comments drew a rebuke from two Democrats running for president, Senators Hillary Clinton and Barack Obama. Obama accused Giuliani of taking what he called the politics of fear to a new low.

Senator McCain has lagged in the public opinion polls and in fundraising in recent months. Some political analysts believe his vocal support for the Iraq war may be hurting his presidential hopes, even though most Republicans remain generally supportive of the U.S. effort in Iraq.

John Fortier is a political expert at the American Enterprise Institute in Washington.

"He [McCain] is close to the president on the war strategy, which is not popular," said John Fortier. "He has really lost some of his oomph [momentum]. And Rudy Giuliani has surprisingly been high in the polls, remained high in the polls because he is not in any way a traditional Republican in terms of issues like abortion and gay marriage and gun control, which matter to social conservatives."

The latest polls indicate that former Tennessee Senator Fred Thompson and former Massachusetts Governor Mitt Romney are the other two top contenders in the Republican field. Thompson has yet to decide on a presidential bid, as has former Republican House Speaker Newt Gingrich.

Recent surveys have suggested that many Republicans are not satisfied with the current presidential field and would welcome the entrance of both Thompson and Gingrich later this year.