The word “populist,” a very old part of the political vocabulary, has lately had a new lease on life. It’s generally used to describe movements of “the people” against “the elite,” whether that takes the form of the French Revolution or a revolt of American farmers. Usually it refers to movements that are said to be “left-wing,” and in recent years, the word has been almost entirely usurped by Latin America, where charismatic populist leaders have galvanized mass movements and pushed through public spending programs ostensibly designed to aid the poor. Sooner or later, all of them ended in failure – sometimes spectacularly so. Probably the most extraordinary example was Hugo Chávez’s Venezuela. His rhetoric inspired the admiration of left-wing and other would-be populist leaders around the world. Famous Chavistas include Jeremy Corbyn, the leader of the British Labour Party, who as recently as June 2015 praised “the achievements of Venezuela, in jobs, in housing, in health, in education.” Lately, the admirers have gone silent, as the combination of profligate spending, nationalization and mismanagement have created galloping inflation, long lines for food and shortages of all kinds. Ever hopeful, left-wing populism lives on in Greece, Spain and elsewhere. But in most of the rest of the Western world, the most energetic form of populism is “right-wing.” Its “anti-elitism” has new overtones, often taking anti-globalization, anti-trade and anti-immigrant forms. Some of its adherents oppose “political correctness,” which might merely mean that they use racist language. Others like to chant nationalist slogans. But even if they look and sound different, even if they know how to use social media and techniques borrowed from reality TV, the new populists do share something with the old populists. Like their predecessors, they offer fantasies: sketchy plans, vague ideas, unfulfillable promises and, eventually, free money. Far from representing something new, they stand for something old: The very human longing for rapid, unrealistic, simple solutions to difficult problems – plus more cash. Whatever you want to call it – utopianism, romanticism – it seems to return every couple of generations. Populist parties from Hungary to France are now talking about nationalization – because if only The People owned the companies, then everything would be fine. We know that scenario from history, and we know how it ends. “Build a wall” and “make American great again” are Donald Trump’s more famous slogans, but he also claims to have an “economic plan” that calls for $4.4 trillion in tax cuts, on top of the existing deficit with no plausible way to pay for them (which, as my Post colleagues have pointed out, is an improvement on his previous plan, which called for $9.25 trillion in tax cuts with no plausible way to pay for them). This is a twist on the Venezuelan scenario – Trump wants to give people money through tax cuts rather than handouts – but if enacted he would bankrupt the state in exactly the same way. He has also hinted that, having acquired this unprecedented debt, he might default on it. We know that scenario from history, too. A milder version of the free money fantasy was even visible in the debate on the British European Union referendum, when the Leave campaign claimed that Brexit would make it possible to spend 350 million pounds a week on the health-care system. Though the claim was repeatedly disproved (and since the vote has been quietly abandoned), the post-voting polls have shown that of all the arguments made, that was one of the most persuasive: Leave Europe, get more money, no strings attached. Nationalization, spending promises, empty slogans: Politicians who cynically promise the impossible wind up with hyper-inflation if they deliver – or political catastrophe if they don’t. Failed populism often leads to radical populism, and radical populism to violence: When people don’t get what they’ve been promised, they get angry. These were lessons learned in the 20th century, but it looks like we might have to repeat them in the 21st. Nothing is new about this populist moment, only the faces and flags have changed.