The Kellogg-Briand Pact, also known as the Pact of Paris, was a treaty between the United States and other nations "providing for the renunciation of war as an instrument of national policy".
It was proposed in 1927 by Aristide Briand, foreign minister of France, as a treaty between the USA and France outlawing war between the two countries. Frank B. Kellogg, the United States Secretary of State, responded with a proposal for a general pact against war.
After negotiations it was signed in Paris on August 27, 1928 by eleven states - the United States of America, Australia, Canada, Czechoslovakia, Germany, United Kingdom, India, Irish Free State, Italy, New Zealand, and South Africa. Four states added their support before it was proclaimed - Poland (in March), Belgium (in March), France (in March), and Japan (in April). It was proclaimed to go into effect on July 24, 1929. Sixty-two nations ultimately signed up to the pact.
The pact never made any real contribution to international peace and quickly proved to be meaningless, especially after the Japanese invasion of Manchuria in 1931 and the Italian invasion of Ethiopia in 1935.
The pact enabled the creation of the notion of crime against peace -- for committing this crime, the Nuremberg Tribunal sentenced a number of persons responsible for starting World War II (see: Nuremberg Trials).'''
The interdiction of aggressive war was confirmed and broadened by the United Nations Charter, which states in article 2 paragraph 3 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". The consequence of this is that after World War II, nations have been forced to invoke the right of self-defense or the right of collective defense when using military action and have also been prohibited from annexing territory by force, although times, these justifications may seem by some to be straining credulity.