In 1966 the Pennsylvania legislature enacted a law prohibiting coal mining that caused subsidence damage to preexisting public buildings, dwellings, and cemeteries. Based on Pennsylvania Coal Co. v. Mahon[case]Pennsylvania Coal Co. v. Mahon[Pennsylvania Coal Co. v. Mahon] (1922), the Keystone Bituminous Coal Association argued that it should be paid compensation for its inability to mine coal in certain places. The company also alleged that the law prevented the enforcement of its existing contracts that waived liability for surface damage.Takings clause;Keystone Bituminous Coal Association v. DeBenedictis[Keystone Bituminous Coal Association v. DeBenedictis]Contracts clause;Keystone Bituminous Coal Association v. DeBenedictis[Keystone Bituminous Coal Association v. DeBenedictis]

Speaking for a 5-4 majority, Justice John Paul StevensStevens, John Paul;Keystone Bituminous Coal Association v. DeBenedictis[Keystone Bituminous Coal Association v. DeBenedictis] reasoned that a state could exercise its police power to protect the public’s safety and welfare and that no Fifth Amendment taking occurs when landowners are not deprived of all economic use of their property. Observing that the statute deprived the company of less than 2 percent of its coal, Stevens found that Court precedents did not allow the company to divide property parcels into component parts when deciding whether the government was required to pay compensation. In regard to the contracts clause challenge, Stevens found that established precedents allowed contractual impairments judged reasonable and necessary for achieving important public purposes. “It is well-settled,” he wrote, “that the prohibition against impairing the obligation of contracts is not to be read literally.”

Contracts clause

Lucas v. South Carolina Coastal Council

Nollan v. California Coastal Commission

Pennsylvania Coal Co. v. Mahon

Property rights

Takings clause

Zoning