Is war against the law?

International Law , , , , , ,

Is war against the law?

On its face, the question seems almost preposterous.

The United States has been in at least two wars in the last 11 years, and several other military actions.

But the answer under international law is surprising.

A good argument could be made that war — or at least aggressive, unjustified war — is actually illegal.

Of particular relevance is an obscure treaty from the 1920s known as the Kellogg-Briand Pact.

The Kellogg-Briand Pact, also known as the “General Treaty for the Renunciation of War,” was an international treaty signed and ratified by almost every major nation, including the United States.

The terms of the treaty are plain. Article I of the treaty obligates every contracting party to renounce war as an instrument of national policy:


The High Contracting Parties solemly declare in the names of their respective peoples that they condemn recourse to war for the solution of international controversies, and renounce it, as an instrument of national policy in their relations with one another.

Article II of the treaty obligates all parties to settle their disputes by “pacific means”:


The High Contracting Parties agree that the settlement or solution of all disputes or conflicts of whatever nature or of whatever origin they may be, which may arise among them, shall never be sought except by pacific means.

As of January 1, 2011, the United States still lists the Kellogg-Briand pact as a “treaty in force.” Under the United States Constitution, international treaties are the “supreme law of the land.” (Art. 6 cl. 2.)

The Kellogg-Briand Pact has been modified slightly by the United Nations Charter, which permits countries to use force in self-defense and where otherwise authorized by the United Nations Security Council.

Nonetheless, under theories of international law, signatories of the Kellogg-Briand pact – including the United States – risk liability should they go to war for improper reasons.

Indeed, the Nazi war crimes tribunal at Nuremberg described aggressive war as “the supreme international crime” under international law. Nazi leaders like Hermann Goering were sentenced to death for planning, initiating and waging wars of aggression and other crimes against peace.