This new Gallup poll asks an interesting open-ended question, probing why Americans say they oppose a particular candidate. It says something about the state of the campaign today, but also points to probable attack ads just over the horizon. When it comes to Obama, “inexperience” (39%) is by far the reason given most, followed by lack of “trust” (15%) and that he’s “Muslim” (12%). Clinton’s detractors point to lack of trust (24%), followed by they “don’t want Bill Clinton back in the White House” (18%) and then they just “don’t like her” (16%). Finally, John McCain gets tagged with his position on the Iraq War (27%), and GOP brand problems: “he’s too much like Bush/need a change” (25%) and “he’s a Republican” (23%). These numbers are somewhat interesting in and of themselves–although not entirely surprising. But they also clearly foreshadow the major lines of attack each party’s nominee will use against the opposition in the general election.