Keene v. The United States was a case heard by the Supreme Court in 1809 that dealt with the issue of whether or not Congress had the power to grant exclusive trading rights on public lands. At stake in this case was an act passed by Congress granting James Keene and his associates exclusive trading rights on certain tracts of land owned by the federal government, which were located near Fort Massac in Illinois Territory. The court ultimately ruled against Keene, finding that while Congress did have authority over such matters, it could not grant exclusive privileges without violating other constitutional provisions related to property ownership and taxation. This decision established a precedent for limiting congressional powers when it comes to granting special privileges or exemptions from taxes or regulations concerning public lands.

In Keene v. The United States, Chief Justice John Marshall delivered a dissenting opinion in which he argued that the Court should not have dismissed the appeal of William Keene. He believed that there was sufficient evidence to support his claim for compensation from the government due to losses incurred as a result of an act passed by Congress in 1798. Marshall argued that since this act had been declared unconstitutional and void, it could not be used to deny Keene's right to seek damages from the government for losses suffered under its authority. Furthermore, he noted that if such acts were allowed to stand without any recourse or accountability on behalf of those affected by them, then no citizen would ever feel secure in their rights against arbitrary governmental action. Ultimately, Marshall concluded that justice demanded some form of reparation for those who had suffered harm as a result of unconstitutional legislation and urged his colleagues on the bench to reconsider their decision and allow Keene's case proceed forward with full consideration given towards his claims for relief