Politics: How to govern this mess?

We in the West have experimented with a number of political systems: radical democracy of ancient Greek city-states, the republic of Rome, the empire likewise, theocracies, anarchies, kingdoms, democratic republics, parliamentary democracies, colonial empires, military dictatorships, fascism, communism, loose alliances and leagues, and the list could go on.

So, again, we ask: where does that leave us? What form of government is best? Is it perhaps too late in the game to ask such a question? Is any one form suitable for the entire world?