WASHINGTON – Supreme Court Justice John Paul Stevens has hired fewer law clerks than usual, generating speculation that the leader of the court's liberals will retire next year.

If Stevens does step down, he would give President Barack Obama his second high court opening in two years. Obama chose Justice Sonia Sotomayor for the court when Justice David Souter announced his retirement in May.

Souter's failure to hire clerks was the first signal that he was contemplating leaving the court...