Property law (2022): Acquisition: Right of Conquest & Discovery Doctrine

The right of conquest is a right of ownership to land after immediate possession via force of arms. It was recognized as a principle of international law that gradually deteriorated in significance until its proscription in the aftermath of World War II following the concept of crimes against peace introduced in the Nuremberg Principles. The interdiction of territorial conquests was confirmed and broadened by the UN Charter, which provides in article 2, paragraph 4, that "All Members shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any state, or in any other manner inconsistent with the purposes of the United Nations." Although civil wars continued, wars between established states have been rare since 1945. Nations that have resorted to the use of force since the Charter came into effect have typically invoked self-defense or the right of collective defense.

The discovery doctrine, also called doctrine of discovery, is a concept of public international law expounded by the United States Supreme Court in a series of decisions, most notably Johnson v M'Intosh in 1823. Chief Justice John Marshall explained and applied the way that colonial powers laid claim to lands belonging to foreign sovereign nations during the Age of Discovery. Under it, European Christian governments could lay title to non-European Christian territory on the basis that the colonizers traveled and "discovered" said territory. The doctrine has been primarily used to support decisions invalidating or ignoring aboriginal possession of land in favor of modern governments, such as in the 2005 case of Sherrill v Oneida Nation.

The 1823 case was the result of collusive lawsuits where land speculators worked together to make claims to achieve a desired result. John Marshall explained the Court's reasoning. The decision has been the subject of a number of law review articles and has come under increased scrutiny by modern legal theorists.