The North Carolina Democratic Party canceled what looked to be the final debate between Barack Obama and Hillary Clinton yesterday. Hillary had agreed to another debate, but Obama balked, citing scheduling conflicts:

The North Carolina Democratic Party has dropped plans for an April 27 debate, which would have been moderated by CBS’s Katie Couric.

Clinton had agreed to the debate; Obama did not, and the party said in a statement that the clock had run out to organize a debate. The party also cited worries about “party unity,” after last week’s combative debate in Philadelphia, a focused grilling of Senator Barack Obama on topics he would have preferred to avoid. …

The scrapping of the April 27 debate leaves the prospect for further showdowns between the two candidates unclear.

I’d say that it leaves the prospects very clear — Obama will not debate Hillary any longer. And the reasons are pretty clear after last Wednesday’s debacle in Pennsylvania. Obama simply doesn’t fare well when forced to defend himself extemporaneously. He gets almost incoherent, and not just on the supposed “distraction” questions, but also on policy His answers on capital-gains tax increases had Hillary smiling and the rest of the nation wondering if he had bothered to study the issue at all.

Marc Ambinder believes that Obama just doesn’t want to give Hillary any more oxygen, but even that explanation has its problems in terms of Obama as a candidate. If Obama has to worry about Hillary gaining exposure at this stage, it doesn’t bode well for his ability to beat McCain in a similar fashion. The man who transcended experience to charge to the front of the Democratic race has to be able to go toe-to-toe with both the other candidates and the media on a national stage, and Ambinder’s explanation suggests he can’t do that in a competitive environment.

Even worse, after last Wednesday, it looks like a retreat. Obama got a bloody nose, and suddenly he doesn’t want to appear on national TV, even up against a cupcake like Katie Couric. The strategy may be sound, but only if one has no confidence in Obama’s ability to stand up to tough questioning. In fact, his withdrawal from the debate appears to be an admission of exactly that.

This won’t hurt him much in North Carolina, where he will win by a comfortable margin. It may affect Obama’s standing in other primary races if voters perceive him to be running a little scared. People who cast their vote on electability may wonder whether Obama has what it takes to go against John McCain in a general election, and may reconsider Hillary on that basis.