"This is going to be a long road, it's a challenging road, there's going to be some rough and tumble, but I think it's the right thing to do for our country," Hunter, the chairman of the House Armed Services Committee, said at a waterfront news conference.
The declaration to form an exploratory committee allows the 13-term California congressman to begin raising money and organize supporters in early Republican primary states such as Iowa, New Hampshire and South Carolina.
Hunter is a familiar face on Capitol Hill and at the Pentagon as chairman of the powerful panel that oversees military policy. Not so beyond Washington and San Diego, and his White House bid surprised many Republicans.
He had not been on any list of potential 2008 candidates that included more familiar names such as Sens. John McCain of Arizona, Massachusetts Gov. Mitt Romney and former New York City Mayor Rudy Giuliani.
Analysts immediately characterized the quest as a long shot.
"You never say never, but Congressman Hunter faces extremely long odds given that practically no one apart from students of Congress knows who he is," said Jack Pitney, a government professor at Claremont McKenna College. "He's a good member of Congress, a very effective chairman of Armed Services. It's just that he has no following within the party."
Hunter, 58, became chairman of the House Armed Services Committee in 2003 a position he would lose should Democrats take control of the House after the Nov. 7 midterm elections. By making an announcement now, he can begin raising money while still heading the committee.
The Vietnam War veteran, a recipient of a Bronze Star, has made his mark in Congress by advocating for a strong military and border security. He played a leading role in the construction of a 14-mile double fence on the U.S.-Mexico border that is nearing completion in San Diego. He co-authored legislation signed by President Bush last week that would extend the border fence to 700 miles.
Hunter voted against the North American Free Trade Agreement and the Central American Free Trade Agreement and opposed most-favored-nation status for China. This year, he was a vocal critic of a deal that gave a Dubai company control of some operations at six American ports.
Hunter has cruised to re-election since he, as a 32-year-old criminal defense attorney, rode Ronald Reagan's coattails to unseat a nine-term Democratic incumbent. The Riverside native faces token opposition next week in his bid for another term representing San Diego's eastern suburbs.
Hunter was a close ally of former Rep. Randy "Duke" Cunningham, a California Republican who was sentenced to more than eight years in prison this year for accepting $2.4 million in bribes from defense contractors. Hunter has accepted $46,000 in campaign donations from the same contractors at the center of the Cunningham scandal, Brent Wilkes and Mitchell Wade.
Carl Luna, a political science professor at San Diego's Mesa College, said Hunter may be preparing himself for losing the Armed Services Committee chairman slot.
"Duncan Hunter is looking for something to do if the Democrats take control of the Congress," Luna said. "He doesn't want to have to go from being chairman of a powerful committee to just another backbencher."
Things didn't end well for the last California House member to run for president Republican Robert Dornan in 1996. Dornan, a vociferous conservative known by the nickname "B-1 Bob" for his support of military programs and bombastic style, spent his time and money on a fruitless White House bid and ended up losing his House seat to Democrat Loretta Sanchez.