Why did Truman disagree with the mccarran act?

President Harry S. Truman disagreed with the McCarran Internal Security Act of 1950 because he believed it infringed on civil liberties and constitutional rights. He argued that the law's provisions, which targeted suspected communists and their organizations, were overly broad and could lead to unjust persecution. Truman felt that the act undermined American democratic principles, particularly the right to free speech and association. Ultimately, he vetoed the bill, though Congress later overrode his veto.