In 1976, Eldridge Cleaver was asked: "Don't you think that some people in the U.S. are always seeing Communists under the bed?" He replied: "But there ARE Communists under the bed!"

The L. A. Weekly did an article on this a few weeks back.

Naturally, it was met with the usual high indignation * that socialists muster when people call them socialists. Immediately, McCarthy is usually invoked, ignoring the fact that when McCarthy was barreling around like a bull in a china shop, there actually was a direct Soviet influence in many areas of the United States. This continued into later years, and included, according to released KGB records, pumping hard cash into the Vietnam antiwar movement.

This "McCarthyism/redbaiting" defense works, especially on liberals who would rather die than be associated with such things. So the anti-American socialists move forward largely unopposed.

*When checking this link out, it's worth noting the signatures on the letter.