Last week, an ad produced by the North Carolina Republican Party that used the specter of Barack Obama as a club against local Democrats was a center of controversy. This week, we have a new, similar spot to discuss. This one's from Mississippi, and is being used against a Democrat running for Congress there. (Video, via the Politico's Ben Smith, is below.)

The Mississippi ad itself is dark and foreboding, perhaps even more so than the one from North Carolina. It focuses on Democrat Travis Childers, who has been endorsed by Obama -- "liberal Barack Obama," he's called in the ad -- and hits Childers for not denouncing the Rev. Jeremiah Wright, Obama's controversial former pastor, and for saying nothing after remarks made by Obama that some have interpreted as elitist. (Wright has been a big feature of the news cycle recently; we'll have more on him later today.)

John McCain, the presumptive Republican nominee, had condemned the ad in North Carolina. But he appears to have changed his tune on the issue. During a press availability Sunday, McCain justified his shift by referencing recent comments Obama made:

I have said that I will not have any comment on it and that because I thought and I believe that Senator Obama does not share those views. But Senator Obama himself says it's a legitimate political issue, so I would imagine that many other people will share that view, and it will be in the arena. But my position that Senator Obama doesn't share those views remains the same.

Referencing the North Carolina controversy, McCain also said that he would keep saying he thinks the ad should not run, but that he "won't continue to try to be the referee here."