Article I, Section 10, Clause 1:
No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law, or Law impairing the Obligation of Contracts, or grant any Title of Nobility.
But suppose that the state neglects to reserve the right to amend, alter, or repeal. Is it, then, without power to control its corporate creatures? By no means. Private corporations, like other private persons, are always presumed to be subject to the legislative power of the state, from which it follows that immunities conferred by charter are to be treated as exceptions to an otherwise controlling rule. This principle was recognized by Chief Justice Marshall in Providence Bank v. Billings, 1 which held that, in the absence of express stipulation or reasonable implication to the contrary in its charter, the bank was subject to the state's taxing power, notwithstanding that the power to tax is the power to destroy.
And of course the same principle is equally applicable to the exercise by the state of its police powers. Thus, in what was perhaps the leading case before the Civil War, the Supreme Court of Vermont held that the legislature of that state had the right, in furtherance of the public safety, to require chartered companies operating railways to fence in their tracks and provide cattle guards. In a matter of this nature, said the court, corporations are on a level with individuals engaged in the same business, unless, from their charter, they can prove the contrary. 2 Since then the rule has been applied many times in justification of state regulation of railroads, 3 and even of the application of a state prohibition law to a company that had been chartered expressly to manufacture beer. 4