Shmuel Rosner in Ha'aretz has a lengthy discussion of whether Jimmy Carter is anti-Semitic. I think it's pretty clear he's not, or at least that there's no evidence that he is, if by "anti-Semitic" we mean someone who hates Jews and wishes them harm.
The more interesting question is whether Jimmy Carter is "prejudiced" against Jews. From what I've read (and I don't want to rehash it all here), he's prejudiced against Israel and Israelis, and prejudiced in favor of the Palestinians and their leadership, for reasons that have more to do with his own underlying emotional and religious outlook than with any objective analysis of the situation. But while such prejudices are obviously correlated with prejudices against Jews, one can easily have such prejudices without being prejudiced against Jews. Carter, from what I've seen, believes a lot of very foolish things, especially but not exclusively with regard to foreign policy, and the fact that his views on Israel and Israelis are as foolish as his views on economics and foreign policy more generally is hardly evidence of a particular anti-Jewish prejudice.
Agree or disagree with my analysis, I think it's at least clarifying to separate the debate over whether someone is prejudiced, and in what way, from whether someone is a "racist" or an "anti-Semite." To take another example, the professor whom Eugene wrote about yesterday is very likely prejudiced against whites (regardless of his own background), but it's less likely that he's actually a "racist" in the sense of hating whites, wishing them harm, or thinking them inferior.
UPDATE: Here's a related post of mine from the old Bernsteinblog, in which I point out that Harry Truman and H.L. Mencken can fairly be described as "prejudiced" against Jews, but not as "anti-Semites."