Charles River Bridge v. Warren Bridge

US Supreme Court decision of 1837 dealing with the interpretation of corporate charters and states' power to regulate corporations.

The owners of the Charles River toll bridge, in fear of economic competition, sued for an injunction against the building of the Warren Bridge, which the state of Massachusetts had authorized. They claimed that their 1785 charter implied the exclusive right to bridge the river; the state was impairing that contract by sanctioning a second bridge. The Court ruled implicit rights to be invalid and declared that ambiguous clauses must be interpreted in favor of the public over the corporation.