The Senate has shown they will confirm a doorstop if the president wants them to. There are no Teddy Kennedy's who will lead the charge against another Bork. This is one reason why I'll vote for Obama enthusiastically. A President McCain will throw the wingnut zealots the most reactionary, federalist society hack he can find, like bloody bloody meat to a piranha tank. He doesn't care about anything but paying off his rich friends and making war. Whatever our problems might be with Obama we know that he won't do that.The problem is that in order to move these guys, you have to be willing to ignore all this and punish candidates for going against you. But if you do so, you might end up seriously hurting your own interests in the short- to medium-term.
(And that's assuming you can capitalize on it in the long term, which requires a lot of things liberals still don't have.)
So yeah, at the end of the day, it's still better to vote for Obama. And hell, after all this controversy, he might well be a bit more cautious about switching positions to chase the mythical centrist swing voter. He tends to have this problem; he'll jump face-first into a problem, but then muddle his way through to a decent (or even admirable) final solution. Voting for him in November is still the best bet.
But that doesn't mean that now, in July, we can't tell him to watch it a bit.