If you look at the Gallup daily tracking chart, Obama’s numbers have been in the 45-49 percent range and McCain’s have been in the 40-44 percent range. While I can think of many things that can keep Obama’s numbers down, I wonder what it would take to get McCain’s numbers up into the high 40s, let alone low 50s. The larger point I’m making is that historically, convincing voters that your opponent is bad can only get you so far. At some point, you have to give voters a reason to vote for you rather than merely against the other guy. In 2004, for instance, anti-Bush sentiment got John Kerry more than 48 percent of the vote, but because people weren’t particularly hot for him, it couldn’t put him over the top. Even if he can raise doubts about Obama, what does McCain have to do to get more people to rally behind him? I’m not so sure.