Sure there is. There's also a Liberal Party. They're both in Wew York, but that is part of America, after all. They're both obviously viable, since they've been around forever. And they do have elected officeholders, since NY election law allows a candidate to run as the candidate of more than one party; if the R or D is acceptable, he gets the nomination.
I was talking about a national political party, capable of winning at all levels.