(Corrects 15th paragraph to delete reference to Obama teaching at the University of Illinois; he taught at University of Chicago Law School) (Adds Chicago rally) By John Whitesides, Political Correspondent AMES, Iowa, Feb 11 (Reuters) - Democratic presidential contender Barack Obama drew a contrast with rival Hillary Rodham Clinton on the Iraq war on Sunday and said it was unclear how she planned to end the conflict. On the day after he formally launched his 2008 White House bid, Obama said on a campaign swing through Iowa that even before the war began it was possible to see the dangerous consequences of a U.S.-led invasion of Iraq. "Even at the time, it was possible to make judgments that this would not work out well," the Illinois senator told reporters, indirectly contrasting his stance with presidential rivals Clinton and John Edwards, who both voted to authorize the war in 2002. Clinton, now a war critic who has promised to end the conflict if she wins the White House, has been criticized by some Democrats for her 2002 Senate vote on authorization and for not renouncing the vote. Edwards, the party's 2004 vice presidential nominee and a former senator from North Carolina, has called his vote in 2002 a mistake. Obama was not in the Senate at the time of the vote but opposed the war from the start. He has proposed a phased withdrawal of U.S. troops from Iraq to be completed by the end of March 2008, and he told reporters he was uncertain how Clinton intended to end the conflict. "I am not clear to how she would proceed at this point to wind down the war in a specific way," Obama said when asked to evaluate Clinton's Iraq stance. "I have tried to consistently present a responsible course of action that recognizes our national security interests in the region but would allow us to start redeploying our troops," he said. Clinton came under pressure again on Saturday during a campaign trip through New Hampshire to explain her 2002 Senate vote. "Knowing what we know now, I would never have voted for it," she said, adding she was not casting a vote to authorize preemptive war but intended to give President George W. Bush the authority to send inspectors back in to Iraq. "I do not believe that most of us who voted to give the president authority thought he would so misuse the authority we gave him," he said. Obama, a first-term senator and former Illinois state legislator, has quickly jumped into the top tier of a crowded Democratic presidential field along with Clinton and Edwards. His early opposition to the increasingly unpopular war is a centerpiece of his stump speech, drawing big cheers on a two-day swing through the state that traditionally kicks off the presidential nominating fight. He repeatedly said voters should demand a clear plan on how to end the war from all the Democratic candidates. CHICAGO RALLY On Sunday afternoon, he flew to his hometown of Chicago for a boisterous rally attended by more than 8,000 people at the University of Illinois-Chicago. "The time has come for us to end this engagement in Iraq," he said, saying he was proud he had been "consistent and constant" in his Iraq message. Some anti-war hecklers demanding a cut-off in funding for the war interrupted his speech at one point. Obama will conclude his campaign swing with a rally in New Hampshire on Monday. Obama also had a sharp response for Australian Prime Minister John Howard, a Bush ally who said Obama's proposals would create chaos in the Middle East. "I think that will just encourage those who want to completely destabilize and destroy Iraq, and create chaos and a victory for the terrorists to hang on and hope for an Obama victory," Howard said on Nine Network television. Obama said it was "flattering" for a Bush ally to attack him the day after he formally launched his presidential bid but noted Australia had contributed 1,400 troops to the war compared to 140,000 U.S. troops. "If he's ginned up to fight the good fight in Iraq, I would suggest that he calls up another 20,000 Australians and send them to Iraq," he said. "Otherwise it's just a bunch of empty rhetoric."
