It's always tempting to blame unpopular developments on our intellectual adversaries.

Still, London-based Wall Street Journal editorial writer Sohrab Ahmari makes a pretty convincing case that emerging immigration restrictions  can rightly be blamed on progressives, who have for many years inhibited free debate about Islam, nationalism, and terror.

Ahmari writes in today's Wall Street Journal:

The irony is that freedom of movement is unraveling because liberals won central debates—about Islamism, social cohesion and nationalism. Rather than give any ground, they accused opponents of being phobic and reactionary. Now liberals are reaping the rewards of those underhanded victories.

Liberals refused to acknowledge the link between Islamist ideology and terrorism. For eight years under President Obama, the U.S. government refused even to say “Islamism,” claiming ludicrously that U.S. service members were going to war against “violent extremism.” Voters could read and hear about jihadists offering up their actions to Allah before opening automatic fire on shoppers and blasphemous cartoonists.

Mr. Obama’s linguistic exertions didn’t repress the truth. They merely opened the space for others to express it—and sometimes to grossly distort it, by suggesting, for example, that all 1.4 billion Muslims are terrorists or sympathizers and should be kept out.

The left also largely “won” the debate over Muslim integration. For too many liberals, every Islamist atrocity was cause to fret about an “Islamophobic” backlash. When a jihadist would go boom somewhere, pre-emptive hashtags expressing solidarity with threatened Muslims were never far behind.

Liberals, on the other hand, were loath to criticize pathologies in the Muslim world and seemed willing to overlook anti-gay and anti-feminist sermons by imams in London and elsewhere. As troubling as what another piece in the Wall Street Journal called President Trump's "refugee bonfire" may be, some of the blame surely rests upon liberals who have suppressed discussion for so long.