Dahlia Lithwick has some interesting thoughts about why liberals tend to be much less focused on the courts than conservatives. I think she's right that the (often nominal) upholding of Warren Court precedents has made liberals more complacent about the direction of the Court than its actual record justifies. This also, I think, helps to explain why the Roberts/Alito "minimalist" strategy of gutting and refusing to seriously apply liberal precedents is worse for progressives than the Scalia/Thomas position that when the Court overturns precedents it ought to do so explicitly.
One thing to add is that, as Sandy Levinson notes with respect to David Broder's bizarre claim that Anthony Kennedy is more powerful than Nancy Pelosi, in some ways the lower priority liberal voters place on the courts is actually more rational. This isn't to say that the courts aren't important, or that liberals wouldn't benefit from putting more pressure on presidents and Senators in judicial appointments. It's also important for liberals to be better informed that what the courts do matters in areas far beyond abortion. But it's also worth keeping in mind that when it comes to health care reform, the courts are pretty much the last potentially countermajoritarian institutional veto point that progressives need to worry about.
--Scott Lemieux