Benjamin N. Cardozo,
Williams v. Baltimore — Opinion of the Court
“ We are told that the many cases upholding an exemption to a railroad at the time of its formation have no bearing upon this exemption which was granted later on. A charter, so it is argued, is a contract, or becomes one when accepted. There is thus a quid pro quo. A privilege conferred thereafter is nothing more than a gratuity, and hence an arbitrary preference irrespective of its motive. But this is to misread the cases and misconceive the rationale back of them. The charter exemption to a railroad does not gain validity from the circumstance that a charter is a contract. ”
