Except that most of the people he actually accused were not Communists.
And, perhaps most importantly, political ideology isn't a crime.
And, perhaps most importantly, political ideology isn't a crime.
Still, I fail to see the similarity between Lieberman and McCarthy in this context.
Calling on companies to withdraw services from Wikileaks (Lieberman) is similar to calling on advertisers to withdraw support from Time magazine (McCarthy).
Overwrought, fear-mongering rhetoric (Lieberman) is similar to overwrought, fear-mongering rhetoric (McCarthy).