Bacon et al. v. Hart was a case heard by the United States Supreme Court in 1861 which involved a dispute over land titles in California. The plaintiffs, Bacon and others, claimed title to certain lands based on Mexican grants that had been confirmed by the Board of Land Commissioners for California under an act of Congress passed in 1851. The defendants argued that these grants were invalid because they had not been approved by the Surveyor General as required under another act of Congress from 1854. In its decision, the court held that while both acts were valid laws enacted by Congress, only one could be applied to this particular situation and it was determined that it was the earlier law from 1851 which should take precedence since it provided more specific instructions regarding how claims should be handled at issue here than did later legislation from 1854. As such, Bacon's claim to title was upheld and his grant confirmed accordingly

In Bacon et al. v. Hart, the Supreme Court was asked to decide whether a contract between two parties could be enforced when one of the parties had died before it was completed and signed. The majority opinion held that contracts must be fully executed in order for them to be enforceable; however, Justice Nelson dissented from this decision and argued that there should not always be an absolute requirement for full execution of a contract in order for it to have legal effect. He reasoned that if both sides had already performed their obligations under the agreement prior to its completion, then they should still receive whatever benefit or detriment they were entitled to as part of the bargain even though no formal document existed at the time of performance. In his view, such agreements should still remain binding on both parties despite any technical deficiencies with respect to formality or documentation requirements since justice would otherwise not prevail in such cases where one party has already fulfilled their end of an agreement only later find out that they are unable to collect what is due them because some paperwork wasn't properly filled out beforehand.