The American soft and hard left have been dangerous for 100 years

This article by Peter Beinart in The Atlantic is very interesting. 

This is the third time in a hundred years that left-wingers have sought to capture the Democrats and the U.S.A. The two previous times involved threats of disorder and transformed America, pushing Franklin D. Roosevelt, John F.Kennedy and Lyndon B. Johnson a long way to the left. Backlashes then followed.

'American exceptionalism' is a Marxist phrase, referring to the fact that the USA has never had a large socialist party, but it is a mistake to overlook how influential both the soft socialist left (think Bernie Saunders) and the hard left (Marxists and Marxist-Leninists) in America have been.  In fact, Communists and the hard left have had a large amount of influence on American politics from 1933 to the start of the Cold War and from the 1960s until the present day. Had FDR died in 1944 and been succeeded by Vice-President Henry Wallace their influence would have been much greater. 

American history tends nowadays to be written by leftists and liberals, which is part of the reason why the anti-Communist reaction in the 1950s is vilified. In fact the Communists were a big internal danger and the far left, in academia especially, still are.