The Green Party is not a far left party, though it's the biggest American Party that is unambiguously left (since the Democratic Party has a sizable, and still dominant though that is becoming less secure, center-right faction), so it's where slightly-pragmatic far left figures end up.

There are far left parties, but they do even worse than the Green's two state lower house seats and no more significant seats anywhere in the country, electing exactly no one to any even modestly significant office.