Liberal and conservative partisans commenced crowing/bellowing on cue this week after President Obama nominated Sonia Sotomayor to the Supreme Court. Everyone knows it's all over but the spinning, but Lefties can take special solace in an odd trend: Liberal high court justices stick to their ideology on the bench while rightward picks have tended to drift to the left over time. Nobody can agree on why.

The poster children most often praised/cursed are Harry Blackmun, William Brennan, Sandra Day O'Connor, David Souter, John Paul Stevens, and Earl Warren -- all of whom were nominated by Republican presidents and went on to side with the liberal bloc on key Court decisions. President Dwight D. Eisenhower ultimately described his appointment of Warren as "the biggest damn-fool mistake I ever made."

Some experts think the trend might be ending, as recent (particularly Republican) presidents take more care to determine their nominees' ideological leanings. "Justices don't stray far when they're a known quantity," said law professor Eugene Volokh at the University of California (Los Angeles).