> But there is no rational reason to pretend to not wield it but then re-import a bunch of drugs from Canada. Permitting trade across the US-Canadian border pr

> But there is no rational reason to pretend to not wield it but then re-import a bunch of drugs from Canada. Permitting trade across the US-Canadian border provides an equalizing force on the prices across the border, even though no drugs actually need to make the return trip (at equilibrium). In other words, allowing the trade puts an upper bound on the difference between the prices charged in the US and the prices charged in Canada - that difference can be no greater than the costs of reimporting those drugs, or else it's cheaper for people to source their drugs from Canada. By disallowing the trade, we allow the difference to grow unbounded.