ABC’s This Week Roundtable featured a thoughtful debate on a fundamental question in presidential politics: is it the policy or the person that matters most? Cokie Roberts posited that the elections are decided more on a “gut check” and that voters pay less attention to the details of tax, healthcare, or other policy matters. But George Will thinks that much of the “gut check” involves a consideration of where candidates stand on those policy issues. This is the more troubling issue for Obama’s supporters: how a far-left candidate is going to sell himself to a center-right electorate.

The McCain team seems to believe Roberts. McCain’s staffers are trying to set up a contrast between Obama and McCain mostly on character questions. The danger? In those debates in the fall, when the entire country is watching, Obama will seem the picture of middle-class virtue and voters will conclude that he doesn’t seem nearly as bad as all those 527 ads have painted him to be. So at some point it may behoove McCain to engage on Obama on the issues. Such criticism may be harder for Obama to explain away than his collegial relationship with Bill Ayers. That is, unless Obama seeks to repudiate his positions (articulated during the Democratic primary) on taxes, trade, Iraq, abortion, etc.

For that reason, although Ms. Roberts may be correct in emphasizing the “gut check,” McCain may have no choice but to start engaging Obama in a battle of political philosophy.