In Foman v. Davis, the Supreme Court ruled that a district court had abused its discretion by denying a motion to amend a complaint after judgment without any justifying reason. The plaintiff, Mrs. Foman, filed suit against her sister and brother-in-law's estate claiming she was entitled to certain property based on an oral agreement with her deceased brother-in-law. After losing in district court due to statute of frauds (which requires certain contracts be in writing), she sought to amend her complaint arguing that the oral contract was enforceable because it was partially performed and not within the statute of frauds purview. However, both the District Court and Court of Appeals denied this amendment stating it would be futile as they believed there wasn't enough evidence for partial performance exception. The Supreme Court reversed these decisions emphasizing Rule 15(a) under Federal Rules of Civil Procedure which states leave should be freely given when justice so requires unless there is apparent or declared reason such as undue delay or dilatory motive etc., none of which were present here according to them.

In the dissenting opinion for Foman v. Davis, Justice Harlan argued that the majority's decision to allow an amendment after judgment was too lenient and deviated from established rules of civil procedure. He contended that such a change should only be permitted if it does not cause undue delay or prejudice to the opposing party, which he believed was not sufficiently considered in this case. Furthermore, he expressed concern about potential abuse of this ruling by litigants who might use it as a tactic to prolong litigation or evade unfavorable judgments. Thus, while acknowledging that amendments are generally desirable for ensuring decisions on merit rather than technicalities, Justice Harlan stressed they should still adhere strictly to procedural guidelines and fairness considerations.