What is containment? In the immediate post-war era, containment became a leading foreign policy for the U.S. & other nations. Developed primarily by Secretary of State George F. Kennan, containment policy sought to contain the spread of communism, but not actively combat it. At first (but not for long) containment was enacted on the international stage through proclamations, plans and ideas like the Marshall Plan, the Truman Doctrine and the domino theory. NATO was also formed during this time, as well as its Soviet counterpart, the Warsaw Pact. Domestically, Americans faced the Red Scare during the later 40s and early 50s. The interstate highway system we know today was established during this time under the Federal-Aid Highway Act of 1956. Civil rights also begins to figure heavily into post-war politics. A new era called the Cold War began in the aftermath of WWII and it dominated world politics for over 40 years.