The essence of power, in the political sense, is the ability to do as you please without regard for others. A nation controlled and dominated, without check, by one person or by a small group is a despotic tyranny; regardless of whether you call it a monarchy, aristocracy or democracy. The opposite situation is every person claiming to be his own governing authority. This is anarchy and anarchies always lead to tyranny or oligarchy by those who are smarter and/or stronger.
The goal should be to balance power so that tyranny can not manifest itself. That was the goal of the framers of the US Constitution. Unfortunately there is a ceaseless endeavor to upset this balance usually for some perceived altruistic idea. The compulsive utopian considers power to always be a force for good as long as the power is in his hand. It was in the name of liberty that the Russian revolutionaries destroyed the old political system. But like a natural force in the physical world, power in the political world does not vanish. Instead it seeks the path of least resistance. And the path of least resistance became the tyrannical hands of the radicals. The cost was sixty million lives.
History clearly shows that we can not put our trust in mere benevolence. Constitutional restrictions, political checks and balances and adequate enforcement of the laws must be in place to restrain human natures appetite for power. A just government maintains a healthy tension between the claims of authority and the claims of liberty.