When George W. Bush stands before a joint session of Congress on Tuesday night to deliver his sixth full-up State of the Union address, as many as a dozen lawmakers arrayed before him will be imagining themselves in his position just two years from now. And all are busily positioning themselves on an issue that he is expected to downplay in the speech: war in Iraq.

What to do in Iraq is destined to dominate the next year of campaigning for the presidency. It is the template by which the news media are now primarily measuring the expanding crop of hopefuls. With so many emerging candidates in Congress, they are tripping over one another introducing legislation, holding news conferences, and forming coalitions across the political aisle to gain press attention and play to the various voting blocs that will determine their fates in 2008.

But only one — Sen. Hillary Rodham Clinton of New York — is playing a strong hand to the center, meticulously building a nuanced record that offers just enough meat to the Democratic base to survive a nomination battle while avoiding a one-sided stance that could be her undoing in a general election campaign.

Clinton displayed a formidable posture at her news conference last week after a whirlwind trip to Iraq and Afghanistan, calling for a cap on the number of troops in Iraq while urging a buildup of forces in Afghanistan. Mixing harsh criticism of Bush’s handling of the war with a firm commitment to maintain a strong U.S. presence in the region, she is skillfully crafting a policy that neither delights nor enrages her party’s anti-war voters.

Most important for a possible general election campaign, Clinton is protecting herself from Republican charges that she is a cut-and-runner by refusing to sign on to any of the proliferating calls for specific withdrawal timetables. She even took issue with the Iraq Study Group’s recommendation for putting the drawdown on a calendar.

While Clinton homesteads the center, backing war limits without withdrawal, her chief rivals in both parties are pitching to the left or right. Last week’s headliner addition to the Democratic field, Sen. Barack Obama of Illinois, boasts of his opposition to the war before it started. John Edwards recanted his 2002 vote as a North Carolina senator to authorize the invasion of Iraq and taunted his fellow Democrats still in Congress to get tough against an escalation of troop strength. Sen. John McCain of Arizona sprinted to the right, steadfastly backing Bush’s plans. And his leading Republican foes, former Massachusetts Gov. Mitt Romney and former New York City Mayor Rudolph Giuliani, echoed the McCain view.

That leaves only Clinton in the middle, where the polls find most Americans to be — on record against the surge but not on board for a speedy pullout. In dodging the black-or-white rhetoric of a solid position, she wins no points for bravery, but in the long run for the White House, success could well be found in the gray zone.

As a Democrat, Clinton stands alone among her party’s major contenders in shoring up her defenses against nearly a generation of charges that the party is weak on defense. That alone gives her a leg up in the electability department.

The danger of holding the center on any hot-button issue is how it opens the door for opponents to cry “waffle.” Amateur centrists, such as Sen. John Kerry in his 2004 presidential bid, make matters worse by saying dumb stuff such as “I voted for it before I voted against it.” The Massachusetts Democrat never shook the flip-flopper label after that explanation for his seemingly contradictory votes on war funding.

Clinton has deftly avoided outright waffling on the Iraq War, even though her detractors in both parties try to make the label stick. The bright and consistent line in her Iraq stance through the years is unapologetic support for removing Saddam Hussein from power while insisting on more competent management of what followed.

By rejecting calls to renounce her 2002 vote for the war, Clinton shields herself from any claim that she would rather have let Hussein stay in power — a charge that her leading Democratic foes will face. And yet she has carefully preserved a right to stand with those voters who detest how the occupation of Iraq has been handled.

Despite backing the authorization, Clinton was among the first in Congress to begin criticizing the invasion’s aftermath, calling attention to insufficient supplies and troop strength just a few months after the war began. And last year she used her seat on the Armed Services Committee to give Donald H. Rumsfeld a tongue lashing that was a turning point on his path out of the Defense secretary’s job.

As the clock ticks away for Bush’s command of the war and potential White House rivals scramble to either end of the field, Clinton can take solace on Tuesday night that she is now sitting on a political platform that could lead her to be standing at the podium when the president discusses the state of the union in 2009.

Contributing Editor Craig Crawford is a news analyst for MSNBC, CNBC and “The Early Show” on CBS. He can be reached at ccrawford@cq.com.