A White House laboring to find a new approach in Iraq said Tuesday it is considering sending more US troops, an option that worries top generals because of its questionable payoff and potential backlash. President Bush said he is ready to boost the overall size of an American military overstretched by its efforts against worldwide terrorism. The military's caution on shipping thousands of additional troops temporarily to Iraq is based on a fear that the move could be ineffective without bold new political and economic steps. Commanders also worry that the already stretched Army and Marine Corps would be even thinner once the short-term surge ended. Bush's newly expressed interest in making the military larger would have little impact on that worry because it will take much longer to add substantially to the size of the military. Generals also question whether sending more troops to Iraq would feed a perception that the strife in Iraq is mainly a military problem; in their view it is largely political, fedby economic distress. Rep. Ike Skelton, the Missouri Democrat who will become chairman of the House Armed Services Committee next month, echoed those sentiments Tuesday. "I'm convinced the Army and the Marines are near the breaking point," Skelton said, while expressing skepticism that a big troop surge would be worth the trouble. With Iraq's burgeoning chaos leaving the Bush administration with few attractive choices, it is studying a possible short-term troop increase there. That proposal is the favorite option of some, including potential 2008presidential contender Sen. John McCain, R-Ariz., and analysts at the conservative American Enterprise Institute, which has strong ties to the administration. Even the bipartisan Iraq Study Group, which advocated removing most combat troops by early 2008, said it could support a temporary increase if U.S. commanders believe it would be effective. Roughly one-third of the 140,000 American troops in Iraq are combat forces. Bush revealed his desire to increase the military's size worldwide in an interview with The Washington Post, days after the Army's topgeneral, Peter Schoomaker, warned that the service would "break" without more troops. The president used no figures, but he said he has asked his new defense secretary, Robert Gates, to produce a plan for increasing the military's size. The Army announced on Tuesday evening that it will accelerate the planned creation of two additional combat brigades as a means of relieving some of the strain on troops caused by repeated and increasingly frequent deployments to Iraq. Both brigades will be ready to join the rotations to Iraq by next April, 11 monthsahead of schedule in the case of one brigade while 17 months ahead for the other. In the latest indicator of the war's financial costs, White House budget chief Rob Portman told reporters Tuesday it was unlikely this year's price tag would be less than last year's $120 billion. Congress has already approved $70 billion toward this year's price tag, and Bush has long been expected to request an additional $100 billion or more in February. Donald H. Rumsfeld, who ran the Pentagon for the last six years, had long resisted calls to increase the size of themilitary, arguing that technological advances and organizational changes could give the Army and Marine Corps the extra capability it needed. Supporters of a surge of American forces in Iraq see it as a potentially decisive move to halt the upward spiral of sectarian killings in Baghdad, which U.S. commanders have identified as the central prize in the Iraq war. They see it as a way to buy precious time to get the Iraqis steadier on their feet. Yet a similar effort, announced with great fanfare last summer, had a dampening effect on violence in targetedBaghdad neighborhoods for a few weeks. As described in a Pentagon report sent to Congress on Monday, that effort, dubbed Operation Together Forward II, ultimately proved insufficient. One big drawback in that case was an inability of the Iraqi government to move sufficient Iraqi troops into those warring neighborhoods. "As the operation progressed, death squads adapted to the new security environment and resumed their activities in areas not initially targeted by" American and Iraqi troops, the report said. Shiite death squads even managed to "leveragesupport" from rogue elements in the Iraqi police, and the violence spiked again, the report said. The American Enterprise Institute issued a report last week recommending a surge of seven Army brigades and Marine regiments starting next spring. A contributor to that report was retired Army Gen. Jack Keane, who was the vice chief of staff at the time the Iraq war was launched in 2003. Andrew Bacevich, a professor of international relations at Boston University, said Tuesday he believes the chances that adding 20,000 or so U.S. troops for several monthswould stabilize Baghdad are "slim and none." The White House on Tuesday denied a conflict between the administration and the Joint Chiefs of Staff, while also offering the assurance that Bush agrees with the military chiefs that any boost in troop levels would be done out of military necessity. "The president has not made a decision on the way forward, and he has asked military commanders to consider a range of options and they are doing so," said Tony Snow, the White House press secretary. Bush is expected to announce his new Iraq approach in Januaryafter Gates visits Iraq. Gen. James Conway, commandant of the Marine Corps, said Saturday that one option under consideration by the president is sending five or more additional combat brigades, which equates to roughly 20,000 or more troops. Conway did not say he opposes that proposal, but he emphasized the potential drawbacks. "We would fully support, I think, as the Joint Chiefs, the idea of putting more troops into Iraq if there is a solid military reason for doing that, if there is something to be gained," he said. "We do not believe that justadding numbers for the sake of adding numbers - just thickening the mix - is necessarily the way to go." The five or more extra brigades would, he said, be units already scheduled to go to Iraq in a later rotation. But he added that using those troops now would mean "a lesser capable" force in the future. "You better make sure your timing is right," he said. "Because if you commit the reserve for something other than a decisive win or to stave off defeat, then you have essentially shot your bolt." The Army's Schoomaker told reporters last weekthat a surge would make sense only under certain conditions. "We would not surge without a purpose," Schoomaker said. "And that purpose should be measurable."