WASHINGTON: As a onetime prisoner of war during Vietnam and decorated Navy officer, Sen. John McCain has based much of his political persona on his staunch support for the military and his consummate credibility on national security.

But as the Arizona Republican prepares to mount a White House campaign, he is putting those military bona fides on the line — aggressively backing an unpopular plan to increase the number of US troops in Iraq at a time that other presidential hopefuls are steering clear of the war or calling for troop reductions.

President Bush is expected this week to announce a plan to send at least 20,000 additional troops to try to halt sectarian violence and bring security to Baghdad — a move widely perceived as an all-but-final push to avert failure in Iraq.

Besides Bush, no politician has more to lose than McCain, the presumed GOP front-runner in 2008 and the plan’s biggest backer in Congress.

Now that Bush is pursuing the McCain approach, the senator could soon find himself defending the policy to a war-weary public in Iowa, New Hampshire and other key election states where surveys show voters are fed up with rising US casualties.

McCain readily admits that the new strategy is likely to result in even more violence — setting up a paradox for him as he strives to succeed an unpopular fellow Republican in the White House by backing an escalation of the very war that has plunged Bush’s approval rating to near-record lows.

Democrats can barely contain their eagerness for McCain to take the blame for a plan that seems to contradict the antiwar message of the 2006 midterm election that stripped Republicans of their once-solid congressional majorities. Former Sen. John Edwards of North Carolina, who is running for the Democratic presidential nomination, went out of his way recently to describe the troop increase as the “McCain doctrine.”

McCain shows no interest in shedding that label.

“If it destroys any ambitions I may have, I’m willing to pay that price gladly,” McCain said Friday after an appearance at the conservative American Enterprise Institute think tank in Washington, where he said the surge “must be substantial and it must be sustained.”

McCain’s calculation is the latest sign that the Iraq war is likely to dominate the 2008 race, just as it overshadowed the elections of 2004 and 2006. But it also shows that McCain, perhaps the best-positioned of any candidate to win the presidency in wartime, is willing to bet it all on a gamble that voters will reward his resolve, as they did for Bush in 2004, rather than punish him, as they did to GOP candidates in November.

Other Republicans are clearly not ready to play those odds.

One of McCain’s top rivals for the GOP presidential nomination, former Massachusetts Gov. Mitt Romney, has so far declined to weigh in.

Democrats, encouraged by the 2006 midterm results and still smarting from a 2004 campaign in which many believe they were too passive on national security, appear to be staking out a strong stance against troop buildups.

The party’s leaders in Congress, Senate Majority Leader Harry Reid of Nevada and House Speaker Nancy Pelosi of San Francisco, laid out their opposition in a letter to Bush last week, and Pelosi warned on Sunday on CBS’ “Face the Nation” that any administration budget request for additional troops would receive “the harshest scrutiny.”

The matter is thornier for the Democrats’ presumed front-runner, Sen. Hillary Rodham Clinton of New York. She has staked out a moderate tone on the war, reserving criticism for the Bush administration’s leadership while consulting military experts such as retired Army Gen. Jack Keane, one of the prime backers of a major troop increase.

If McCain won the nomination, voters could face a stark choice while watching violence unfold. McCain appeared to recognise that on Friday as he addressed the packed American Enterprise Institute conference room.

In a preview of how he plans to answer critics should additional troops fail to defeat the Iraqi militants, he was careful to add that the administration had dug itself into a hole with its post-invasion strategy — an argument that, in effect, blames Bush for not taking McCain’s earlier advice. —Dawn/The Los Angeles Times News Service