Constitutional Law in 1917–1918. II: The Constitutional Decisions of the Supreme Court of the United States in the October Term, 1917

There is little or no homogeneity to the questions to be considered under the head of retroactive legislation. A dispute whether a state has passed a law impairing the obligation of contracts may turn on a question as to the proper interpretation or application of language, or on opposing views of what is sufficient consideration or what agreements are against public policy. It was under the obligation-of-contracts clause that the Pennsylvania Hospital case decided that the power of governmental authorities to exercise eminent domain could not be bargained away. The crucial question is more often whether alleged rights existed than whether undoubted rights have been impaired. The Fourteenth Amendment and the doctrine of vested rights combine to make the obligation-of-contracts clause almost superfluous, as it is difficult to think of any impairment of the obligation of contracts which that clause inhibits which could not equally well be held deprivations of liberty or property without due process of law. This is apparent from the fact that retroactive legislation by Congress is questioned under the due-process clause of the Fifth Amendment, a contract being regarded as a property right that can be interfered with only when there is sufficient justification for what is done.