The judicial branch is headed by the chief justice of the Puerto Rico Supreme Court, which is the only appellate court required by the Constitution. All other courts are created by the Legislative Assembly of Puerto Rico. There is also a Federal District Court for Puerto Rico, and someone accused of a criminal act at the federal level may not be accused for the same act in a Commonwealth court, and vice versa, since Puerto Rico as an unincorporated territory lacks sovereignty separate from Congress as a state does. Such a parallel accusation would constitute double jeopardy.