Here is an excellent article by Walter Williams.
Liberals, Progressives and Socialists
http://townhall.com/columnists/walterewilliams/2012/08/08/liberals_progressives_and_socialists
In Europe, especially in Germany, hoisting a swastika-emblazoned Nazi flag is a crime. For decades after World War II, people have hunted down and sought punishment for Nazi murderers, who were responsible for the deaths of more than 20 million people