In the United States Supreme Court case of The United States v. Thomas Power's Heirs, the court was asked to decide whether or not a certain tract of land in Missouri belonged to the heirs of Thomas Power or if it had been rightfully acquired by the government through eminent domain. At issue was whether an act passed by Congress in 1820 granting lands to settlers who were living on them prior to December 20th, 1803 applied retroactively and included those who settled after that date but before March 3rd, 1819 when Missouri became a state. The court held that since no one could have legally occupied any part of this particular tract until after December 20th, 1803 due to Indian occupancy at that time, they concluded that Congress did not intend for their act from 1820 to apply retroactively and thus ruled against the heirs' claim.

In the case of The United States v. Thomas Power's Heirs, the Supreme Court was asked to decide whether a patent issued by Congress in 1820 for land located in Missouri could be revoked due to non-payment of taxes. The majority opinion held that such patents were revocable and thus the government had a right to reclaim the land if taxes were not paid. However, Justice McLean dissented from this decision arguing that once granted, these patents should remain valid regardless of any subsequent failure on behalf of the grantee to pay their taxes or fulfill other obligations imposed upon them by law. He argued that it would be unjust for Congress to revoke an individual’s property rights after they have already been established and vested with full legal effect through a patent issued by Congress itself. Furthermore, he noted that since no provision existed within either federal or state laws allowing for such revocation then it should not be allowed under common law principles either as doing so would amount to taking away private property without just compensation which is prohibited under both constitutions (federal and state).