Unfortunately Sotomayor is probably the best pick Obama could make from my point of view. She isn’t likely to sway anyone on the court given her limited intellect, and she may just highlight how silly some liberal “legal opinion” really is.
Republicans should politely question her on constitutional issues, and point out the difference between liberal activism and constitutional law, and then allow the vote to go to the floor of the senate. They can vote against her there, but unless the Democrats toss her under the bus for lacking grey matter, the Republicans shouldn’t get too much in her way.
To do otherwise makes the Republicans look mean. That’s the disadvantage we face because the Democrats can always put simpathetic losers up for nomination. When Republicans try to nominate simpathetic judges, their nominees are either old white men, not black enough, not womanly enough, not poor enough, etc. Somehow if you are qualified to sit on the bench, and you aren’t a liberal, you’re unfit to be a judge. The same will never apply to liberal nominees.