Government by the masses only works when the masses are well-educated. If the masses are, by and large, as ignorant as Americans have become, then they're easy to manipulate via fear, and produce government by those least-suited for the task. Sadly, the mass underfunding of public education in the US has been a bipartisan effort- people in the US overwhelmingly choosing lower taxes + poorer public education over higher taxes + better public education- and a self-perpetuating one at that. After all, poorly educated people are also easier to convince to further cut money from education.
The ideal form of government may well be the true Philosopher King, but I'm not sure that such a person has ever existed- or could ever exist. Barring that, self-government by an educated populace has produced the best results so far- quoting Churchill: "democracy is the worst form of government except all those other forms that have been tried."