Over time Republicans have learned how to play the race card more effectively, which is to say more subtly with each passing electoral cycle. It looks like John McCain has taken the half-science, half-art of race-baiting attacks to a new level, in part because he goaded not only voters but Barack Obama himself to take the bait.

To explain, let me back up a second to mention a recent New Republic piece by John Judis ("The Big Race," May 28, subscription required). In it, Judis reviews recent political science experiments on the use of racial phrases and imagery. The main lesson is that overtly racial appeals backfire, but subtle and coded ones work just fine because whites are willing to both express and respond to racial prejudices so long as they don't feel like they are doing so. (That is, so they can take comfort in the self-delusion that their prejudices aren't, well, prejudicial.) The political science literature on this "new racism" also helps explain why, as the recent Rasmussen poll found, only 22 percent of Americans found John McCain's Spears/Hilton negative ad against Barack Obama racist, but 59 percent thought Obama's dollar-bill comment in response to the ad was racist.

Add to this literature the brilliant insight by Adam Serwer over at the American Prospect about how whites respond to allegations or insinuations of racism. "In a dispute about race, the McCain campaign knows it will end up with the larger half," Serwer argues. "For the most part, most white people's experience with race isn't one of racial discrimination. They can only relate to racial discrimination in the abstract. What white people can relate to is the fear of being unjustly accused of racism. This is the larger half. This is why allegations of racism often provoke more outrage than actual racism, because most of the country can relate to one (the accusation of racism) easier than the other (actual racism). For this reason, in a political conflict over race, the McCain campaign has the advantage, because saying the race card has been played is actually the ultimate race card."

The Republican attack machine knows what it is doing. The race -- er, contest -- between Obama and McCain is tight and is tightening. (Rasmussen even has McCain now slightly ahead.) Obama needs to start fighting back with some attacks of his own that demonstrate equal measures of punch and sublety.