Davidson v. Lanier was a case heard by the United States Supreme Court in 1860. The dispute centered around two parties, Davidson and Lanier, who had entered into an agreement for Davidson to purchase certain slaves from Lanier at a set price. After making payments on the agreed-upon amount but before receiving title to the slaves, Davidson learned that they were already mortgaged to another party. He then refused to make any further payments or take possession of them until he received assurance that his title would be clear of all encumbrances upon payment in full. The court held that since there was no evidence of fraud or misrepresentation on either side and both parties had fully performed their obligations under the contract up until this point, it should be enforced as written with respect to its terms regarding payment and delivery of title free from encumbrance upon completion thereof.

Justice Grier delivered the dissenting opinion in Davidson v. Lanier, arguing that the majority's decision was contrary to established precedent and would lead to a dangerous expansion of federal power. He argued that Congress had no authority under the Constitution to pass laws regulating private contracts between citizens of different states, as this was an issue reserved for state legislatures. Furthermore, he noted that if such a law were allowed to stand it could be used by Congress as a pretext for interfering with any contract made between citizens of different states - including those involving property rights or personal services - which would be unconstitutional and detrimental to individual liberty. Finally, Justice Grier asserted that even if there were some constitutional basis for passing such legislation it should not apply retroactively since doing so would violate fundamental principles of justice and fairness.