Though pragmatism may be your goal, stopping short of fully following your ideology to its logical conclusion may cause contradictions. Within the libertarian movement, minarchists are just as supportive of the right to property as anyone else, but when the mechanics of those rights spill over into how other things might work, it becomes apparent that their support is not as strong as they believe it is.
Though minarchy could work as a non-coercive institution if “taxes” were paid voluntarily (although it becomes debatable if that still qualifies as minarchy), many who support it argue that national defense is a service that the free market is incapable of providing. And without this national defense, they argue, natural rights such as life, liberty, and property would be subject to whether or not some outside force decides to invade and take those rights away.
There are a number of problems with this position, such as: rights would then be subject to the whims of the minarchist military and government; the dichotomy of “lacking a military means invasion” does not actually exist; the burden of proof is on the minarchist to show that defense means could not be privately funded (after all, people generally purchase insurance and protective services to make sure their property is not damaged or invaded regardless if the attacker is nature or human). Those are good discussion points, but there is a deeper philosophical issue that should be examined.
Again, according to the minarchist, the threat of losing your rights justifies what would otherwise constitute an unjustifiable act of coercive taxation in order to fund the defense organization. I do not hold that there are never situations when coercion against peaceful individuals is justified as there are always a number of lifeboat scenarios that someone can come up with.
The difference, however, between a lifeboat scenario and a state-supplied military is that the former is almost always a temporary situation and usually involves extraordinary circumstances while the latter is a situation that is guaranteed according to the minarchist’s view of social orders. If stateless societies with voluntarily-provided militaries (i.e. free market-based) are unworkable, then if tried they would undoubtedly revert back to or would be swallowed up by some form of state. Even if it were the only function of it, the state would of course then fund its military through taxation.
This means that the taxation is fundamentally unavoidable for any society in any sort of “equilibrium.” If a minarchist holds that he has the right to his body and his property, how can he simultaneously hold that the state has the right to his property to fund a national defense? Something is either exclusive to an individual or it is not. Under the minarchist’s point of view, individuals only have the right to a portion of their property. Failure to pay what you do not have the right to would be a violation of the right of the state, making the consequences of the pursuit of the taxes owed justified.
Now the question becomes this: how much does the state have the right to? Who decides how much military protection is enough military protection? Does the amount owed to the state remain static or does it change? Is it possible for everyone in a centrally planned system to agree on any of that?