He supported it in the 90s, then was "undecided" again for a while, then flat-out against it, then changed his mind again in early 2012 and is now in support of it.
Interestingly, as FiveThirtyEight showed at the time, he waited until there was more than 50% support among Democratic voters before finally coming out in support of it this most recent time. (That tipping point happened a couple of months before he announced the "evolution" of his believes.)
