Why was the Kellogg-Briand peace pact ineffective?

The United States refused to sign it.

It had no means to enforce its provisions.

Germany was not admitted to the League of Nations.

Most citizens did not believe their governments would follow it.

It had no means to enforce its provisions.

Explanation:

Practically, the Kellogg-Briand Pact did not live up to its aim of ending war or stopping the rise of militarism, and in this sense it made no immediate contribution to international peace and proved to be ineffective in the years to come.

The Kellogg-Briand Pact was made after WWI (not until 1928) and was therefore of no significance to that war. The war helped to cause the pact, but the pact did not impact the war. The countries who signed the pact were hoping to prevent another war from happening.

The Kellogg-Briand Pact was violated in 1931 when Japan invaded Manchuria.

The primary problem and reason for failure was that the treaty provided for no means of enforcement or sanctions against parties who violated its provisions.

the social contract theory