Further - the U.S. with its large size, diversity, and history of populism should be a good case study on effective and pluralistic government.
This is the type of thinking that repeatedly gets us in trouble. We naively assume that the great experiment we have implemented in America can be implemented in any country despite entrenched cultures that are not receptive to pluralistic governance. We're so hubristic in this regard we assumed we could fix bayonets and push an oppressive government out, and then a stable democracy would "naturally" emerge because it is a natural law.

While we may have the American idea for over two centuries it has taken us well over 200 years to even coming close to recognizing it, and yet we insist on imposing our ideology on others. Lets not forget the U.S. has more people in prison than any other nation other than China, and I think that is relevant. We enforce the rule of law with an increasingly militant police force and a less flexible legal system. Perhaps out of necessity, but if that is the case it indicates that our pluralistic form of governance is not working for all, so like any other nation we have our percentage of malcontents. The problems are significantly worse in Iraq and Syria. Pluralistic governance seems like a great idea, but I still question its feasibility as a solution in many countries. Then it begs the question do we care more about the form of government or human rights? Can a more oppressive government effectively suppress ethnic hatred within its society, leading to an uncomfortable peace? Or is it better to remove these governments and push for ballots instead of reason? The results in Afghanistan, Iraq, and Libya indicate we need to rethink this.