Since a sitting President will very, very rarely sign authentic autographs for “fans” while in office, the best way to catch them is BEFORE they win!  This signed card was gotten while Barack was in the early days of campaigning.  You can almost always tell where a celebrity is on the “fame” spectrum at the moment they signed the autograph you’re looking at it; if it’s legible (or almost), that usually means that they’re on their way up. Or down.