In this case, Phineas O. Foster, Roger A. Heirne and George J. Blakeslee (the owners of the steamboat Swan) brought a suit against Gorham Davenport and other commissioners of pilotage in Mobile Bay and Harbor for charging them an excessive fee for their services as pilots on the Swan's voyage from New Orleans to Mobile Bay. The plaintiffs argued that they were only required to pay $100 per trip according to state law, but instead had been charged $200 by the defendants without any legal authority or justification for doing so. The Supreme Court ultimately ruled in favor of the plaintiffs, finding that there was no legal basis upon which such an exorbitant fee could be imposed on them; thus ordering a refund of all fees paid beyond what was legally authorized under state law at the time ($100).

In the case of Phineas O. Foster, Roger A. Heirne, and George J. Blakeslee v Gorham Davenport and Others, the dissenting opinion was that the state law requiring pilots to be licensed by a board of commissioners in order to navigate ships within Mobile Bay should not be enforced against steamboats from other states because it violated Article IV Section 2 of the Constitution which guarantees citizens "the Privileges and Immunities" of each state's citizens when traveling between them. The dissent argued that this licensing requirement constituted an undue burden on interstate commerce as it would require out-of-state vessels to pay for pilotage services even if they had their own experienced navigators onboard who were familiar with local waters; thus creating an unnecessary expense for those vessels while providing no benefit or protection to anyone else involved in navigation through Mobile Bay. Furthermore, since there is no evidence that such a regulation has been adopted by any other State or Territory along its coasts or rivers, allowing Alabama’s licensing scheme could set a dangerous precedent whereby every State can impose similar regulations on foreign shipping without regard for constitutional limitations on their power over interstate commerce.