Complex sentence: However, the federal government is not restricted by the Contract Clause of the U.S. Constitution that prohibits "Law (s) impairing the Obligation of Contracts"--by its terms, this prohibition applies only to state governments.
Split into simpler sentences: However, the federal government is not restricted by the Contract Clause of the U.S. Constitution that prohibits "Law (s) impairing the Obligation of Contracts". By its terms, this prohibition applies only to state governments.