There is party Left front (http://leftfront.ru/) In Russia, rules Sergey Udolicov. Why in USA no school desks as Left front?
USA is two party system. You can vote Conservative or Progressive, but if you vote for any other party you are usually throwing away your vote. Because only 1 candidate within your voting district can be elected. The far left and far right sometimes try to influence the main parties, but for the most part they are pushed to the side. When there are more conservatives than progressives, usually it allows the conservatives to move further to the right on their policies because they do not have to cater so much to the moderates to get votes and support. So when the balance of power shifts, this is not seen so much in one party winning over the other, but rather in the policies of both parties shifting further to the right or left. This also means that each party has to unite together a diverse group of different interests, and at times this can become very awkward and comical. In the USA, the Democratic Party does not have to worry so much getting support from the far Left. Who else is the Left going to vote for? The hard Left is often very frustrated at the Democratic Party, but better them than the other Party. And when the Democratic Party desperately needs the votes, they are too busy moderating their polices to cater to moderates. So the hard Left is mostly left out of the decission making process.
You can thank super pacs and corporate media for that. The system is designed so that corporations can keep us in a two party system.