The Marxists haven't "returned", they never left (no pun intended. These people take the long view and they eat while we sleep. All things considered, they've largely gotten what they wanted and a quick look at the 10 planks of the Communist Manifesto will confirm it. The only thing left for them at this point is to get brazen about it which is why it looks like they've "returned."
I read that 1 in 4 Americans make below 18K, which is in America absolute povery line and that number continue to grow as overall income drop. That and add to it mass illegals of low income and an elite that is seperated and non-serviced to the country, a gigantic debt and you have what was in Russia in 1905...all that is needed now is the catalyst of an international embarresment of a lost war or some such to spark the organization of these peoples by the communists.