While serving in the Senate, Davis appeared before the United States Supreme Court in 1837, representing the defendants in "Charles River Bridge v. Warren Bridge". The plaintiffs were proprietors of the Charles River Bridge, a toll bridge constructed between Boston and Charlestown in 1786, and the defendants were proprietors of a competing bridge to which the state had issued a charter in 1828. The plaintiffs argued that the defendant's charter infringed on their charter, in which they claimed the state granted them an exclusive right to control the crossing. Davis and cocounsel Simon Greenleaf argued that the rights granted to the Charles River proprietors had to be interpreted narrowly, and that the state had not granted them an exclusive right. The court found for the defendants, with Chief Justice Roger B. Taney's decision echoing the defendant's reasoning. The Charles River Bridge charter would be acquired by the state in 1841, during Davis's next term as governor.