A pretty good move. Bush has nailed down his base with this move (and the killing of the AWB extension that will get lost in Tom DeLay's circular file...).
This is a problem for Kerry, in that the pollsters are clear on this subject. Now that Bush has come out foursquare in favor of an Amendment, Kerry has to find a way to find some daylight between him and Bush. Kerry also has to deal with the backdoor crowd who are going to want John Effin' to take a stand for barebacking.
I expect a meltdown from Andrew Sullivan on this, unfortunately. He's been ready to break from Bush for some time.
Be Seeing You,
Chris