Hi Namu Butsu!
Interesting, complicated topic. It came up a few times at e-sangha and provoked some heated and fruitful discussion.
A couple questions come to mind. Firstly, Buddhism is often described as "going against the grain of the world"; it's a path of transcendence. Quite a few of its beliefs, practices and goals run intentionally counter to what ordinary people conceive of as happiness. To me, this raises some question as to whether it can be successfully applied as a political philosophy, since politics is concerned with mundane needs and worldly ends.
Since most people aren't Buddhists, how could they be convinced to embrace a political order that is unconcerned with their (worldly) needs? Usually people want things like jobs, daycare, decent schools, and prosperity. Is dharma really about such issues?
Second question has to do with Lenin and Mao. Both of these leaders not only condoned, but fully endorsed "revolutionary terror", and subsequently state terror, as a political instrument. Mao proudly compared himself to Qin Shi Huang, one of the most violent emperors in Chinese history. How would you reconcile such a point of view with Buddhist ethics?