Might Makes Right

This is the underlying principle of the world.  Whether it be a moncarchy, republic, democracy, fascism, communism, or any other -ism, all forms of government rely on this precept for its source of power and existence.

That being so, what makes one form of might more legitimate than another?  Or are they all equal?

"Legitimacy" must be measured from a utilitarian perspective.  The happier the population (and the future population!), the more "legitimate" the government.

In other words, might does not make right.