Democracy

“Democracy is the worst form of government, except for all the others.”

― Winston S. Churchill

Democracy is the only political system capable of maximizing the sense of freedom and self-determination experienced by the citizens. Since all of the happiest countries are democracies, and there is no reason to believe that any of the inherently authoritarian alternatives would better serve their citizens in the long run, it's pretty easy to conclude a this point that democracy represents a political best practice.