Keystone Bituminous Coal Assn. v. DeBenedictis

In Pennsylvania Coal Co. v. Mahon, 260 U. S. 393 (1922), the Court reviewed the constitutionality of a Pennsylvania statute that admittedly destroyed “previously existing rights of property and contract.” Id., at 413. Writing for the Court, Justice Holmes explained:

“Government hardly could go on if to some extent values incident to property could not be diminished without paying for every such change in the general law. As long recognized, some values are enjoyed under an implied limitation and must yield to the police power. But obviously the implied limitation must have its limits, or the…