What would support Trumans argument that every nation must choose between two alternative ways of life

In a dramatic speech to a joint session of Congress, President Harry S. Truman asks for U.S. assistance for Greece and Turkey to forestall communist domination of the two nations. Historians have often cited Truman's address, which came to be known as the Truman Doctrine, as the official declaration of the Cold War.

Explanation:

to extend a country’s power and influence