I don't get that either. The republicans helped him get elected. And his fellow dems threw him out of the boat. Why would he vote with them?
He even said he will vote how he feels would be the best vote, not just along party lines. Sounds like an independent to me.
Because he is a Democrat, and he is being true to his party, even if the current crop of dummies forced him out to make an anti-war statement. And when he runs for re-election again in six years, I'd bet it will be as a Democrat again.
Cuz he's a hooooooor.