This is not to say that everything the populists say is untrue. Hitler, too, was right to grasp that mass unemployment was a problem in Germany. Many of the agitators’ bugbears are indeed worthy of criticism: the European Union’s opacity, the duplicitousness and greed of Wall Street bankers, the reluctance to tackle problems caused by mass immigration, the lack of concern for those hurt by economic globalization.

These are all problems that mainstream political parties have been unwilling or unable to solve. But when today’s populists start blaming “the elites,” whoever they may be, and unpopular ethnic or religious minorities, for these difficulties, they sound uncomfortably close to the enemies of liberal democracy in the 1930s.

The true mark of the illiberal demagogue is talk of “betrayal.” The cosmopolitan elites have stabbed “us” in the back; we are facing an abyss; our culture is being undermined by aliens; our nation can become great again once we eliminate the traitors, shut down their voices in the media, and unite the “silent majority” to revive the healthy national organism. Politicians and their boosters who express themselves in this manner may not be fascists; but they certainly talk like them.