Projected talking point:
"We weren't obtructionists, we were bipartisan -- look, more Democrats voted for Roberts than against him. The Republicans are the ones in lockstep, not us..."
Absolutely. Voting for Roberts was a smart move. The ones who didn't vote for the guy they all admit was the most brilliant witness to ever testify before the judiciary committee cannot justify their no vote to the rest of the country. To their uber-liberal interest groups, yes, but not the country. Now the group has some cover, as you mention, but the ones who voted against him really don't, although they'll say anything to get around their votes, even going so far as to vote against the next person for not being as brilliant as Roberts (the guy they voted against).
It's going to be very ugly no matter what happens. If Bush doesn't nominate an obvious conservative, he's going to feel the heat, and if he does, the confirmation battle will be intense.
Talking point my you-know-what. A judge with the sterling credentials that Justice Roberts has should not have gotten one nay vote.