US President Barack Obama appears to have secured what President George W. Bush couldn't: bipartisan support for an unpopular and faltering war. Despite expressing an uneasiness about the details, lawmakers are poised to back Obama's plan to send 30,000 more troops to Afghanistan after getting assurances that some soldiers and Marines will begin withdrawing in July 2011. The strategy marks the largest expansion of the war since it began eight years ago. Critics conceded that Obama will have little trouble early next year getting Congress to provide an added $30 billion or $40 billion to carry it out. The president's chief military and diplomatic advisers faced more questioning from lawmakers Thursday after encountering only tepid criticism Wednesday from members of the Senate Armed Services and House Foreign Affairs committees. Anti-war Democrats, who rose to power because of voter opposition to Bush's strategy in Iraq, said they are skeptical that the troop buildup is necessary or will work. But at the same time, party leaders - who were among Obama's biggest supporters in his campaign for president - said it was unlikely that they would try to block the deployments or the money he wants. Critical to winning Democratic support was a July 2011 deadline that Obama set to begin troop withdrawals. Michigan Sen. Carl Levin, chairman of the Senate Armed Services Committee, said setting the date will "produce the sense of urgency in the Afghan government that has been lacking up to now." Republicans won assurances from Defense Secretary Robert Gates that the 2011 withdrawal date was flexible. They otherwise supported the troop buildup because it fulfills a request by U.S. commanders in Afghanistan for more soldiers and Marines. "Once we achieve our objectives - an Afghanistan that can defend itself, govern itself, control its borders and remain an ally in the war on terror - then we can reasonably discuss withdrawal, a withdrawal based on conditions, not timelines," said Senate Republican leader Mitch McConnell of Kentucky. Sen. Joe Lieberman, a Connecticut independent, told Gates, "You've struck exactly the right balance." Gates said the president was committed to begin pulling at least some troops out by the target date. But the president will have the authority to change gears after the Defense Department conducts a formal assessment in December 2010. "We're not just going to throw these guys in the swimming pool and walk away," Gates said of the Afghan security force. Rep. John Murtha, D-Pa., chairman of a military spending panel, told reporters he anticipates the Pentagon asking for $40 billion for the war early next year and Congress approving it. "It's not likely that there would be any circumstances where the president would lose this battle," he said.