Continuing the previous post, visualize the following scenario.
Muslims are starting a jihad and invading Europe to convert everyone to Islam at gunpoint. They are animated by burning zeal for their religion and are willing to pay great costs by risking defeat and death at the hands of the Christians.
To everyone’s surprise, the Christians turn out to be apathetic, shiftless, and pragmatic (which is how they actually are, anyway) and do not resist the invasion militarily. After a bit of vocal complaining, they submit and end up converting en masse.
The Muslims mercifully no longer face the unpleasant insolence of the non-Islamic Europe; the former Christians are upset but not overmuch and very little in the long term.
This invasion is a unique non-repeatable historical event, so no appeal to general consequences of a rule allowing invasions can be made.
Regardless now of welfare effects, is the jihad proved to be libertarian after all? Not according to Rothbard or any other reasonable person, but apparently yes according to Lesterian liberty: the imposed costs are at their lowest.