What bill did president truman veto because he said it would create a thought police?

Under the advisement of the Department of Defense, the State Department, the CIA, and the Department of Justice, President Harry S. Truman decided to veto the bill entitled the Internal Security Act of 1950. On its face, this bill appeared to be anti-communist but upon analyzing the bill more closely, Truman felt the bill would actually further communism and be a detriment to the United States. Thus, it was vetoed.