Well, we know Bwawney Fwank is a card-carrying Marxist member of the 'progressive' caucus, a wholly-owned subsidiary od the "Democratic Socialists ofAmerica", which is the U.S. arm of the Socialist Internationale. I dare say the other 9 signatories probably are, too.
And if the Rep party hasn't publicized this, they are just as guilty. There are a lot of heads worthy of "pillars of fire."