> who owns your child? You or the state?

If your child is your property, then what happens on their 18th birthday? Is that some kind of theft? There's no foundation in common law or natural law for property that stops being property at a certain moment, so the glove doesn't fit.

There is a legal concept that does fit, and that is the concept of a Ward / Warden relationship. Fun fact, the word Warden comes from the Anglo-Norman dialect dialect of French, while the word Guardian comes from Old French which often used G where Anglo-Norman used W, so from their origin they are the same word.

Guardianship is a messier concept than ownership, which is why libertarians don't like it, but it is INCREDIBLY common. You own some land but it's a designated historical site so zoning law says you have to protect its beauty, you're a guardian. You've inherited the family wealth but a majority of your education has been brainwashing you into believing you must preserve it for the next generation - you're a guardian. Parent, you're a guardian.

As you can see, there is sometimes no structure to enforce against the guardian treating his ward as property that can be destroyed or sold for scrap. For example a 3rd son of money can blow the family treasure, a king can run his country into ruin.

In a healthy functioning country, the state (or church) is your guardian - and that's something you want, because you don't want to live in a world where some mafia can walk up and grab everything you have.

An argument I have with ancaps is how their voluntary society can prevent someone from extorting money from everyone else and using that money to raise an army and police force to be able to extort more money. They always come back with the same arguments about private armies and private courts - to which I say "well, the IRS is precisely that, so why aren't you hiring blackwater to fight them?"

Unfortunately we mostly live in failing states. Transnational criminal elites have converted them from cohesive nations into multi-ethnic power struggles because it allows them to gain control by playing the groups against each other. So our governments no longer play a parental role, but now are more like orphanages.

The solution is not to eliminate the state (our only bulwark against transnational criminal elites controlling everything), but rather to construct new states (churches, political machines, etc) which we can trust.