The really unworkable thing about libertarianism is that they always talk about the threat of physical force like it's the end all be all, when it's the least of forces to be hated.
Economic force is overwhelmingly the most powerful force, but it gets a pass from them on almost every issue. As Ghandi said 'economic violence is the worst form of violence'.
If you take the cities water supply with your army it's wrong, but if you buy it with your bank it's okay? The poor people who can't afford your fee to drink are going to starve in both cases; what's worse: in the latter case people will BLAME the thirsty for their own death.
We are taught to worship the strong of wallet in the same way we used to worship the strong of arm.