The legal case against attacking Iran

Article II of the Constitution requires the president to “take care that the laws be faithfully executed,” and Article VI says that treaties are part of the “supreme law of the land.” Since the Senate overwhelmingly ratified the United Nations Charter as a treaty in 1945, the president is constitutionally required to abide by Article 51 of the charter. This provision allows states to use military force in self-defense only when responding to an “armed attack.” Preemptive attacks are another matter.

In 1981, the United States joined in the U.N. Security Council’s unanimous condemnation ofIsrael’spreemptive assault on an Iraqi nuclear reactor. British Prime Minister Margaret Thatcher put it bluntly: “Armed attack in such circumstances cannot be justified. It represents a grave breach of international law.”…

The United States was also the central player at the decisive moment for self-defense in the 20th century: the judgment at Nuremberg. We remember these trials for their condemnation of genocide. But this was not their central focus. The main charge was that the Nazis had waged aggressive war — and this required the Allies to endorse the limited doctrine of self-defense enshrined in traditional law.