jimmy carter and the southern baptist convention

In a recent article for the Australian online news site The Age, former U.S. President Jimmy Carter explained his reasons for cutting ties with the Southern Baptist Convention (SBC). This was reported on several blogs I follow, and I was surprised because I remembered hearing the same thing several years ago.

But now, Beliefnet reveals that there may be much less to this story than first appears:

But I have this question: What does it mean for Jimmy Carter to resign from the SBC when (1) individuals aren't members of the SBC but of local churches that are associated with the SBC? And, more importantly, (2) when he continues to be a member of his SBC church and teaches Sunday School there?

I have a great deal of respect for Jimmy Carter because of his humantarian work since he left office, but I have no idea what he is trying to do here. Maybe it's a Baptist thing that I just don't understand, but how can a person cut ties with his denomination while continuing in a leadership position in a church that still belongs to that denomination?