Felix Frankfurter,
Inland Waterways Corporation v…
“ Illegality cannot attain legitimacy through practice. But when legality itself is in dispute-when Congress has spoken at best with ambiguous silence-a long continued practice pursued with the knowledge of the Comptroller of the Currency is more persuasive than considerations of abstract conflict between such a practice and purposes attributed to Congress. More than half a dozen agencies have thought it their duty to safeguard deposits in nearly a hundred banks by transactions similar to those before us. ”
