Is there a difference between an apologist and an apologizer?

It's not just a question for Catholics, as NRO's Jonah Goldberg notes at The Corner:

I love this item from Washington Post fact-checker Glenn Kessler. Romney says that Obama is going around the world apologizing for America. The headline: "Romney's claim that Obama is an apologist for U.S. is based on distortions."

Indeed!

An apologist is someone who zealously defends something, not someone who apologizes for its failures.

The WaPo piece has been corrected since Goldberg posted about it. But apparently no apology was made by fact-checker Kessler for confusing an apologist with an apologizer.

On a semi-related note, see my fact-checked essay, "Be A Catholic Apologist — Without Apology".