Republicans and democrats.

We actually have a discussion already going on this topic. It can be found here:
http://www.philosophyforum.com/forum/philosophy-forums/branches-philosophy/philosophy-politics/4703-two-party-government-system.html

Oh alright. Thank you.

The history of single-party governments, especially in the modern age, is especially dreary and the results have been so disastrous for the citizens that they have revolted at the earliest possible opportunity.