In the wake of the Brussels attack, a number of European voices have called for closing the continent’s borders to Muslim migrants. There are at least some Americans saying the same thing. In a recent Fox News interview, Donald Trump warned that Tuesday’s violence in Brussels was “just the beginning” and that “at this point, we cannot allow these people to come into our country.” One complicating factor here is that it appears that the perpetrators of this attack, as well as the recent terror attack in Paris, are by and large not Muslim migrants. Rather, they are the children of Muslim migrants, born and raised in Europe. Defenders of large-scale Muslim migration will insist that barring new migrants would have absolutely no effect on the native-born women and men living in Europe’s impoverished Muslim ghettos. But is that really true?

How you feel about Muslim migration depends, to a large degree, on your moral instincts. Consider one of Trump’s more cutting remarks in his Fox interview: “That’s the problem with the liberal policies of this country and this world, it’s acting like it’s our fault. It’s not our fault, OK, it’s not our fault. It’s their fault.” Those who believe Europe ought to welcome Muslim migrants in large numbers might reply that it is our fault, at least in part. You could reasonably argue that the chaos spreading throughout the Arab world is a consequence of the Iraq invasion and the bloody conflicts that have followed or that the market democracies that have profited from capitalist exploitation are to blame for poverty and violence everywhere. It all depends on your particular ideological bent.