Complex sentence: Scalia concedes that legislation compelling judges to carry out federal legislation has been passed but considers that the nature of the courts, which occupy a vertical hierarchy that requires consideration of prior decisions by federal or state courts, exempts this from applying in this case.
Split into simpler sentences: Scalia concedes that legislation compelling judges to carry out Federal legislation has been passed. But he considers that the nature of the courts, which occupy a vertical hierarchy that requires consideration of prior decisions by Federal or state courts, exempts this from applying in this case.