No matter what happens next, last week’s stunning “Leave” vote on Brexit has permanently disrupted the status quo ante. Both the Conservative and Labour parties are facing major leadership changes; Conservative Prime Minister David Cameron has resigned, and Labour’s Jeremy Corbyn has been besieged by his shadow cabinet for his tepid support of the Remain option. Stock markets worldwide continue to tumble and the British pound has taken a beating. The Sunday New York Times lead story took a somewhat hysterical tone when it announced that the Brexit vote “is already threatening to unravel a democratic bloc of nations that has coexisted peacefully for decades.” And the strong supporters of Remain are now determined, it seems, to predict the worst, perhaps in the hope that Great Britain will take the opportunity to “reconsider” its decision in light of the global economic hit that occurred the day the Brexit vote was announced.

As I recently argued, the Brexit vote was complicated, given the pros and cons on both sides. But now that the voting has occurred, the correct response is to put the fear-mongering aside and to think hard about the two major issues, so central to the Brexit debate, which will continue to vex Britain and the EU — trade and immigration. On this score, it is important to realize that those two issues are distinct. The argument for free trade is pretty clear — but with the much murkier issue of immigration, it is virtually impossible to come up with a knockdown argument in favor of either fully open or fully closed borders.

Let’s start with free trade. Here, the basic economic principle of comparative advantage works with equal force in both domestic and international markets. The most efficient form of production comes through a division of labor in which all parties provide those goods and services at which they are, relatively speaking, better at producing than anyone else. Thus, even if nation A were better than nation B at all forms of production, it hardly follows that nation B should remain idle. Instead, it should produce in that area in which it has the smallest disadvantage relative to nation A. So long as trade between the two nations remains open, both nations should on balance be better off than they would have been if each kept tariff walls high against any imports. The mutual exchange produces higher outputs across the board, and thus fuels growth in both nations. The principle is scalable, so that the more nations that come to the table, the greater the gains from trade, in both the international and domestic arenas. The substantive goal is to make the borders among sovereign nations porous.