The following is my speculation about where the plot of the story is going. It is just speculation, but on the off-chance that any of it is correct and non-obvious, it will contain spoilers.

Solid control by a central authority seems to be more difficult for magic folks. (e.g. A few dozen Death Eaters nearly brought down the government). I assume this is because Apparition makes control of transport impossible, everyone having wands makes control of dangerous weapons impossible, and the Imperius curse makes central authority untrustworthy and spreads paranoia.

Voldemort realized that the situation doesn't have a democratic/liberal/libertarian solution and that an enlightened despotism is the only way to prevent another Dark Lord from rising up every few decades to seize control. Because of this, Voldemort, who really is a Light Lord, used his campaign of terror to try to take control of the Ministry of Magic, and impose his absolute, magically enforced rule over everyone.... Until he was defeated by baby Harry. Now, he is using his new form and identity to identify the best possible new Light Lord at Hogwarts (hence the war-games).

He will groom the new candidate to be his replacement, then stage his return as evil Voldemort, be defeated by the new Light Lord, who will bring peace and order as the absolute dictator.