Question

Were americans correct in worrying that domestic communists endangered their security?

Answer 1

Personally I don't believe that the domestic communists in the US endangered the security of the ordinary Americans. I believe that Senator Joe McCarthy went on a witch hunt because of the concerns of the large corporations and them worrying about their security, not of the average American. In fact, true communists or socialists only want better working and living conditions for the downtrodden in this case of the US citizens so far from being a threat to their security they are fighting for increased security for those people. An international example is the country of Viet Nam which is a communist or socialist government but which threatens no one and is a peaceful, successful country as opposed to the hysteria of the 1960's and 1970's about the communists of North Vietnam. 

Answer 2

Yes, the Americans were very worried that the domestic communists can endanger the security of the country. they have the fear of spreading the information about America that could help Russia. the Hiss and the Rosenberg's communists were executed as result of being spies to USSR about USA.