The Usurper: A modern example would be McCarthyism (sp) from the early period after WWII, where anyone with even the remotest connection to the communist party was persecuted. Bad hysteria based on all communism being bad.

...... Even though just a few years before, they were our brothers in arms against Hitler and we were supplying them with essential supplies through which many sailors died from U-boat attacks as we knew if Russia fell, Hitler would have only the west to concentrate on.

I still remember pictures of the two sides meeting when they'd over run Germany and Berlin and the joy and comradeship shown by all soldiers for their fellow soldier at the joy of defeating the Nazi menace.