D. The fear of the spread of Communism
The soviet union lost the most lives during world war 2
A lot of countries had totalitarian leaders during this time, such as Germany (Hitler), Italy (Mussolini), Japan (Tojo), Spain (Franco), Portugal (Salazar), and possibly many others, too.
She repeats it to lessen the connotative power of the word because her audience has ignorant people. She's suggesting that oppressive and superficial description are irrelevant to a person's personality.
If Congress stretched their powers too far, it is likely that the Supreme Court would step in after a lawsuit and rule that Congress was acting outside the scope provided for it in the Constitution.