Actually, I can't count. There haven't been 4 Dem primaries, there have been 5 primaries so far, but none of the Dems except Clinton went to Michigan, as I recall. And performed really badly there too, considering she was unopposed by the other two first tier candidates.

Considering that Clinton's fortunes may be waning, why does everyone assume that only Obama will benefit from that? If Clinton keeps sinking, that doesn't mean everyone is jumping on the Obama bandwagon.

So of course Edwards is still in the running. You can't count any of the top tier candidates out at this early stage because a million different things can and will happen to shake things up in a 3 way race.