SEATTLE — Barack Obama acknowledged he hasn’t been a perfect president as he asked some , supporters to help him win another term and ask themselves a different question than the tradition standard an incument faces of “are you better off than you were four years ago?” The question he wants to frame the election: “Will we be better off if we keep moving forward?” In a half-hour speech regularly interrupted by the partisan audience, Obama sought to paint Republicans as the group that wants to go back to policies that didn’t work in the last decade and Democrats as the party trying to move forward. Some of the loudest cheers came whenever he mentioned something involving gay rights, and he worked that theme into many areas of the speech just a day after he said he personally supports the rights of same-sex couples to marry, although the issue should be decided by each state. “If you’re willing to work hard, you should be able to find a job…give your kids a chance to do better…no matter what your last name is, where you come from… no matter who you love,” he said.