The fifth amendment's just compensation clause forbids taking private property for public use without just compensation. The report analyzes the original meanings of terms used in the clause, the police power limitation, and case law divergence. The contract clause prohibits States from passing any law impairing the obligation of contracts. Noting that 20th century holdings by the Supreme Court have virtually read the clause out of the Constitution, the paper discusses recent decisions which indicate the clause is still alive. Five other constitutional provisions that might be invoked to defend economic liberties are discussed: the due process, negative commerce, uniformity, ex post facto, and equal protection clauses. Standards for interpreting the just compensation and contract clauses are proposed. Selected examples of case law and commentaries are appended.