The 'far left' is next to nonexistent in America. Our 'far left' are centrists at best in comparison to European political parties.
What we DO have is 60-80% of the population behind all sorts of actual liberal policy ideas which then never get enacted because all of our elected officials are more conservative than the districts or states the represent, because the party machinery always gets behind more conservative candidates for what they consider strategical reasons, to try and bite into Republican voters, assuming they'll get the 'left' behind them no matter what. And we see the browbeating constantly on sites like DU or DK - you 'have' to support every candidate with a (D), even if they absolutely suck on the issues that are most important, even if, 20 years ago, that candidate would have been a middle of the road Republican by their stances on various issues. It's a mighty victory when Democrats pass legislation that originated decades ago with Republican think tanks.