How did Truman's anti-Communist stance affect his actions after he became president

His political stance was that Communism should be stopped, and that is why he brought many laws, prosecuted Communists in the States and among other thing he brought Truman's doctrine, which is seen by many historian as the beginning of Cold War.

Explanation:

After war ended Truman believed that the greatest threat to the world comes from Soviet Union. He believed that spreading of Communism could destroy all the things they fought for during the war. That is why he managed to threw out many supporters and sympathizer of Communism from the government.