On November 30, 1950, after the Chinese Communist army entered the Korean conflict, President Harry Truman announced that he was prepared to authorize use of atomic weapons in order to achieve peace in Korea.

Additionally, Truman accused the Soviet Union of using Communist Chinese forces to spread Communism into Asia.

In response to questions from the press regarding what measures the U.S. might take, Truman responded “whatever steps were necessary” to contain communist expansion in Korea.

A reporter then asked “Will that include the atomic bomb?”

Truman replied, “That includes every weapon that we have.”

Source: History.com