President George W. Bush and the Democratic-controlled Congress lurched toward a veto showdown over Iraq on Wednesday, the US commander in chief demanding a replenishment of war funding with no strings and House of Representatives leader Nancy Pelosi counseling him, "Calm down, take a breath." Bush said imposition of a "specific and random date of withdrawal would be disastrous" for US troops in Iraq and he predicted that lawmakers would take the blame if the money ran short. "The clock is ticking for our troops in the field," he said. "If Congress fails to pass a bill to fund our troops on the front lines, the American people will know who to hold responsible." Bush spoke as the Senate moved toward passage of legislation that would require the beginning of a troop withdrawal within 120 days, and would set a goal of March 31, 2008, for its completion. The House approved a more sweeping measure last week, including a mandatory withdrawal deadline for nearly all combat troops of Sept. 1, 2008. Both bills would provide more than $90 billion to sustain military efforts in Iraq and Afghanistan. After passage, the next step would be a House-Senate compromise measure almost certain to include conditions that Bush has said he finds objectionable, and the president's remarks seemed designed to lay the political groundwork for a veto showdown with the new Democratic majority later this year. Confidently predicting his veto would be sustained in Congress, he said, "Funding for our forces in Iraq will begin to run out in mid-April. Members of Congress need to stop making political statements, and start providing vital funds for our troops. They need to get that bill to my desk so I can sign it into law." One key Democrat with longtime ties to the Defense Department, Rep. John Murtha, said Bush was exaggerating, and he estimated the real deadline for a fresh infusion of funds was June 1. Gordon Adams, a former Clinton administration official specializing in defense issues, said the Pentagon has authority to transfer existing funds between accounts. "So into June, while it's painful, it's possible" for the military to maintain operations, he said. Democratic leaders, determined to force Bush to change course in Iraq, also disputed his contention that Congress would be to blame for any funding difficulties in a war they have vowed to end. "Why doesn't he get real with what's going on with the world?" said Senate Majority Leader Harry Reid. "We're not holding up funding in Iraq and he knows that. Why doesn't he deal with the real issues facing the American people?" Pelosi responded to Bush with a blend of conciliation and challenge. "On this very important matter, I would extend a hand of friendship to the president, just to say to him, 'Calm down, take a breath," she said. "There's new Congress in town. We accept your constitutional role. We want you to accept ours." Democrats took control of Congress in January after elections framed by voter dissatisfaction over a war that has now claimed the lives of more than 3,200 US troops, more than 50,000 Iraqis and cost more than $350 billion (â‚¬262.2 billion). "This war must end. The American people have lost faith in the president's conduct of the war. Let's see how we can work together," added Pelosi. Whatever the outcome, the confrontation bore similarities to a veto fight of a dozen years ago. At the time, a new, Republican-controlled Congress promised steep spending cutbacks to balance the budget, and a politically weakened president of the other party refused to go along. A pair of government shutdowns ensued - including one that lasted 21 days - and Republicans bore the brunt of the public's unhappiness. In the end, the new Republican majority surrendered, and Bill Clinton exploited the episode to help rehabilitate his standing with US the voters. Apart from the Iraq provisions, the Senate legislation includes about $20 billion in domestic spending that Bush did not ask for. Republicans readied an attempt to strip out much of it, and Bush listed it as among the bill's objectionable features.