This article analyzes the U.S. Supreme Court’s record in twenty-first-century federalism cases and compares these rulings with rulings issued in the late twentieth century, a time when the Court was aggressive in invalidating federal acts on federalism grounds and reluctant to limit state authority when reviewing state acts. The twenty-first-century Court has displayed a continued willingness to enforce limits on federal power when reviewing federal statutes but has been less willing than in recent years to sustain state laws with an eye to preserving state autonomy.