WASHINGTON (AFP) - Democrats in Congress are plotting a new round of political attrition over Iraq, apparently confident their hand will strengthen the longer their clash drags on with President George W. Bush. A day after Bush vetoed their bid to compel him to start bringing combat troops home within months, his foes vowed to renew their battle. But signs mounted they were mulling a medium-term strategy, hoping that political ground on the unpopular war would shift in their favor, rather than immediately sending Bush a new timeline for withdrawal he is sure to veto. "This bill is not the last word," Steny Hoyer, the Democratic majority leader in the House of Representatives, said Wednesday. Another senior Democrat, Representative David Obey, added: "it is going to be a long time before this issue is disposed of," in comments on the vetoed 124 billion dollar war funding bill. In narrow political terms, the president's move appeared to heap pressure back on Democrats, who believe voters gave them a mandate to end US combat operations in Iraq by handing them control of Congress last year. With his constitutional powers as commander in chief, and given the fact they cannot command a two-thirds majority required in Congress to override Bush's veto, Democrats appear unable to do more to force Bush's hand. First, the two sides must agree on a new war bill acceptable to both -- that process started with a meeting at the White House Wednesday which congressional leaders from both sides said was positive. By standing his ground on withdrawals, Bush may seek to paint Democrats as impotent on budging Iraq policy, despite their control of Congress and fierce pressure to end the war from their political base. Democrats are also on the hot seat as funds for US troops will run out within months, should a new bill not be signed by Bush --- and they are loathe to risk the political price of being seen as not supportive of the troops. Democrats counter that they funded the troops, and that Bush's veto blocked the resources. As the weeks wear on, and absent an easing of violence convulsing Iraq, Democratic leverage may grow -- especially if Republican members of Congress face public anger over the war in the run-up to 2008 elections. "The time will come -- I am not sure when, but I hope soon, that tipping point will be reached when the Republicans finally say to their president: 'Enough,'" said Democratic Senator Dick Durbin after the Bush veto. "Then we will be able to override vetoes and pass legislation that will make a meaningful change on the policy of his war." Professor Steven Smith, a congressional expert at Washington University in St Louis, said Republicans may eventually have the critical role if they judge their position is unsustainable and policy needs to change. "I think (Bush) would prefer to maintain control over the policy and continue to maintain as much Republican support as he can by modifying the policy," Smith said. "The alternative may be, eventually, that Congress will override his veto." Some Republicans are thought to have made clear to the White House that they backed Bush only for a limited time to see if the plan to surge nearly 30,000 more US soldiers into Iraq will help to still raging violence. General David Petraeus, now in charge of the Iraq campaign, said in Washington last week he would report back on the progress of the surge in September. "The administration itself has said we should see meaningful results over the summer. If we fail to see meaningful results, that support will dissipate quickly," Smith said. Hoyer signaled on Wednesday that Democratic leaders would next target 2008 Defense authorization and appropriations bills due to be sent to Congress by the White House in May and June. He has indicated the next bill will include benchmarks for Iraq -- such as passing a law to share oil revenue, curbing religious violence and disarming militias. "Failure to meet benchmarks could cost Baghdad billions of dollars in nonmilitary aid, and the administration would be required to report to Congress every 30 days on the military and political situation in Iraq," The Washington Post reported Thursday. Other options circulating among Democrats are the idea of benchmarks for the Iraqi government on political progress. But some Republicans have signaled resistance to a cutoff of funding if certain goals are missed. Democratic Representative John Murtha may push an attempt to finance war operations for only a couple of months.