Taking measures to prevent any extension of communist rule to other countries was called this guided president truman's foreign policy.

Containment--Truman's foreign policy was based on containing the spread of communism to other countries.

Under Truman's foreign policy, the focus became stopping the spread of communism. The Marshall Plan was used to fund vulnerable countries and prevent falling to communism. The creation of NATO was also used to protect democratic countries in the case of a threat.