A US agreement on a timeline to pull troops from Iraq could erode some of Democrat Barack Obama's appeal as the anti-war presidential candidate. Obama and his Republican rival, John McCain, would claim vindication, experts said, if a deal being negotiated by Washington and Baghdad set even a conditional and qualified target date for the withdrawal of US troops. An accord promising to wind down the war in Iraq could deprive Obama of an issue that has brought him much attention and mobilized Democratic voters, said James McCann, a Purdue University political science professor. A central pledge of Obama's campaign is a 16-month timetable for a US military withdrawal from Iraq. By contrast, McCain has always backed the Iraq war as well as the increase in US troops in early 2007, known as the “surge,” that helped drive violence down and set the stage for a reduction in US force. “The Iraq issue has been kind of difficult for McCain to deal with,” McCann said. “If the White House can work out some sort of agreement to demobilize in Iraq ... that could make life a little easier for McCain, because he has been forced over the last months to defend his hawkish position on Iraq.” “On the other hand,” McCann added, “it could demonstrate that Obama had a credible claim when he suggested a deal could be worked out.” Secretary of State Condoleezza Rice, in Baghdad on Thursday, said the United States and Iraq were indeed close to a deal that would extend the presence of US troops beyond 2008. She said it might well include an “aspirational” timeline for their mission. Conventional wisdom Conventional political wisdom dictates an Iraq pullout accord would be a boost to McCain, said Larry Sabato, director of the University of Virginia's Center for Politics. A timetable deal “lowers Iraq on the list of voters' concerns, and re-emphasizes the success of the surge, and McCain was right and Obama was wrong on the surge,” he said. But Sabato added that he thinks a pullout timeline could nonetheless help Obama's campaign. “It cuts both ways,” he said. “Any news out of Iraq, good or bad, reminds people of the 4,300 lives we've lost, and nearly a trillion dollars we will have spent by the time we get out,” Sabato said. Iraqi officials have said they would like to see all US combat troops withdrawn by 2010 or 2011, but it is not clear how explicit such language would be in the agreement. A commitment to withdraw combat troops in 2010 would resemble Obama's plan for a 16-month timetable for withdrawal. McCain has said troop reductions are likely but he does not want to commit to a firm timetable. The Brookings Institution's Michael O'Hanlon says the timeline in any Bush administration agreement with Iraq is unlikely to be as firm or as fast as Obama advocates. If a timetable for the United States to leave is announced soon, both campaigns are likely to claim it shows they had good instincts in foreign affairs, said Anthony Cordesman of the Center for Strategic and International Studies. “Obama will claim vindication and McCain will say he is right about the surge and victory,” Cordesman said. But the actual timetable for the troops to leave will be determined by how quickly Iraq can move toward stability, he added. – Reuters __