"What would happen if Congress split into four parties? This."

"If we assign members of Congress to political parties based on the spending votes, we end up with four parties. The Liberals bucked the Democratic president to oppose the spending package. The Democrats voted for it. The Republicans followed Boehner and McConnell's lead. The Conservatives didn't. It gives us maps of the House and Senate that look like this, with the actual party composition underneath."

http://www.washingtonpost.com/blogs/the-fix/wp/2014/12/15/welcome-to-the-four-party-congress/?tid=sm_fb

I would be really, really okay with 4 parties. Although, I guess, a lot of the passion would migrate to the extremes - but the money would probably stay in the middle. It could get weird. Or it could give people political breathing room? Probably not. I don't know, maybe.