US presidential candidate Barack Obama opened the door Thursday to altering his plan to bring US troops home from Iraq in 16 months based on what he hears from military commanders during his upcoming trip there. "I'm sure I'll have more information and continue to refine my policy," he told reporters on the airport tarmac here. During his presidential campaign, Obama has gone from the hard-edged, vocal opposition to Iraq that defined his early candidacy to more nuanced rhetoric that calls for a phased-out drawdown of all combat brigades that, at a rate of one or two a month, could last 16 months. He has said that if al-Qaida builds bases in Iraq, he would keep troops either in the country or the region to carry out "targeted strikes." Responding on Thursday, Republican National Committee spokesman Alex Conant said, "There appears to be no issue that Barack Obama is not willing to reverse himself on for the sake of political expedience. Obama's Iraq problem undermines the central premise of his candidacy and shows him to be a typical politician." But Obama insisted that his position has not changed at all.