Andrew Sullivan's interested in the question of Sandy Berger's role in the Clinton campaign and flags this bit from USA Today:

"He has no official role in my campaign. He's been a friend for more than 30 years. But he doesn't have any official role," Clinton said.

But he's an unofficial adviser, Susan asked?

"I have thousands of unofficial advisers," said Clinton, "and, you know, I appreciate all of that. But he has no official role in my campaign."

I have no idea whether or not this exhausts Berger's informal role as part of Team Clinton, but what you hear if you talk to people in left-of-center national security circles in Washington is that one of Berger's informal responsibilities is basically to get in touch with former Clinton administration foreign policy hands and warn them in no uncertain terms that if they back Barack Obama, Clinton will win anyway and those who supported her rivals will pay the price. My sense is that everyone, probably including Berger himself, understands that he can't actually be given a job in a Clinton administration one way or another.