My short formulation for the borders debate:

1. As Praxeologists, we look for aggression in actions, not policy.
2. Neither open borders policy or full-restricted border policy (therefore anything in between) is free of aggression because when the state removes borders and doesn’t let the expropriated owners retake their property/protect them, and lets outsiders use those properties, this violates the obligation the state has toward the expropriated, in the same way a jailer would have an obligation to protect the jailed, regardless of it being right or wrong jailing. When the state restricts borders, one cannot freely use/homestead an unowned property like in the wilderness.
3. A libertarian either supports non of the border policy positions or supports one that commits fewer aggressions as second best solution proposal.
4. Hoppe’s guaranteeing the immigrants solution gets us close as possible to what would otherwise have happened if private property rights were protected and markets were free. And it should be preferred as the better option as it commits fewer aggression and prevents civil wars and mass plumber that would happen in an open border scenario. 

Any libertarian should accept at least first three arguments. If they have any sense, all four.
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