The presidency of Donald J. Trump is an American phenomenon. But it's not just an American phenomenon.

It makes sense to see the rise of a right-wing cultural populist with authoritarian instincts as an outgrowth of American trends, from the long-term evolution of the Republican Party to the outsized influence of Fox News and talk radio rabble-rousers. But these American developments aren't happening in isolation. For complicated reasons, similar developments are happening in countries around the world — in Russia, India, Turkey, and all over Europe.

A couple of months ago, after elections in the Netherlands and France in which anti-liberal parties underperformed, it was possible to believe that the populist wave had crested and begun to recede on the continent. But not anymore. Those setbacks now look like a temporary hiatus in a much broader-based shift away from the centrist liberalism that, until recently, had prevailed in Europe uninterrupted since 1989.

Hungary and Poland are already governed by anti-liberal populists (as are Slovakia, Macedonia, Croatia, Serbia, and Greece). In last month's elections in Germany, a far-right populist party (Alternative for Germany) managed a stunning third-place showing with 12.6 percent of the vote, marking the first time since the end of World War II that such a party has won seats in the legislature. (It will hold more than 90.)

And now, in an election on Sunday, the Austrian electorate just handed a victory to the center-right People's Party, which is led by 31-year-old populist firebrand Sebastian Kurz, and delivered a strong second-place showing to the far-right Freedom Party. The center-left Social Democratic party, meanwhile, came in third. This is just the latest example of the electoral collapse of the center-left in Europe.

As Slate's Yascha Mounk has pointed out, the outcome of the Austrian vote is likely to be repeated later this week in the Czech Republic, where anti-establishment parties are on track to win a majority of the votes, and where the leading candidate for prime minister, Andrej Babiš, is a cross between Trump and Italy's Silvio Berlusconi. Add a Babiš victory to recent populist advances in Germany, Poland, Hungary, and Austria, and we're left with a picture that's as clear as it is ominous.

The last time European electoral trends were headed so starkly against liberalism was in the 1920s and '30, when liberty was extinguished across the continent.

Now, there are two important differences between the interwar years and our present moment.

For one thing, the radicalism of the political movements that spread across Europe in the wake of World War I was driven by a worldwide economic collapse. The situation today is much less dire. Many economies are stagnating, but generous safety nets and an absence of hyper-inflation prevent the pain from being felt too acutely by too many people. That doesn't prevent them from gravitating to right-wing populist messages. But it does keep those who market such messages from winning a larger share of the vote in national elections — at least so far.

But this shouldn't ease our minds. On the contrary, it should prepare us for the dangers we may need to confront in the event of a major economic shock. Combine current illiberal trends with a sharp economic downturn and things could turn extremely ugly extremely fast.

And that brings us to the second difference between the interwar era and our own. Eighty years ago anti-liberal parties promulgated comprehensive ideologies (communism, fascism) that promised to unify highly differentiated national communities around a common purpose or goal. Recognizing the greater challenge of doing so under the more pluralistic conditions of the present, today's populists try the opposite tack, using social media and other forms of technology to sow rancorous dissension with fake news and generous helpings of disinformation. The hope is that anti-populists will end up so confused, distracted, and riven by discord that the populists will win and maintain power despite their lack of majority support in the electorate.

This is one of the distinguishing marks of Putinist populism, and we're likely to see more of it throughout the Western world over the coming years. When no one can say for sure what is true and what is a lie, political leaders are given a free hand. In some cases, they can even get away with murder.

For now, such a suggestion still sounds shocking. But if the anti-liberal tide continues to rise, it won't for long. In the world of right-wing populism struggling to be born in the United States and across Europe, politics, entertainment, national pride, bitter resentment, and a continuous swirl of technologically disseminated rumors and lies will combine to dissolve ideals of good government and protect our leaders from public scrutiny and oversight.

Welcome to the post-liberal world.