It seems to me that the US political system is a classic example of why 'intelligent' design gets sub-optimal results more often than evolution. The US system was designed; the rest of the world uses whatever system survived millennia of revolution, civil war, and coups d' état, where nobody sat down and said "How do we ensure that the people have power?", but instead they asked "How do we stop the peasants from revolting again?". The latter approach is a LOT slower, but leads to a much more efficient result. Giving the citizens choices they don't want is not a recipe for success - unless you WANT fanatics and extremists running the place.
The occasional fist-fight wouldn't hurt either.