Javier Milei is a rock star.

The president of Argentina was, in fact, in a Rolling Stones cover band as a teen.

But now he plays stadiums — like Buenos Aires’ 8,400-capacity Luna Park — as a political phenomenon, a charismatic cross between Donald Trump and Milton Friedman.

Except that Milei, a former economics professor himself, is more free-market than Friedman, in theory at least.

He’s a devotee of the most notoriously “intransigent” free-market thinker of them all, the great Austrian economist Ludwig von Mises.

As Mises’ masterwork, the nearly 900-page opus “Human Action,” turns 75 this year, Milei has made a cover version of sorts: his own new book, “Capitalism, Socialism, and the Neoclassical Trap.”

He took to the stage at Luna Park to promote it after the Buenos Aires International Book Fair canceled him in retaliation for cuts he’s made to government arts funding.

Clad in a long leather jacket yet wearing a tie, his collared shirt untucked, Milei was a nerd gone wild, belting out a hard-rock number called “Panic Show” by a band named La Renga before launching into an econ lecture.

That might sound like a buzzkill, but Milei’s brand of political economy is full-on “anarcho-capitalism,” and it’s finding fans even among Argentines who’ve long benefited from their government’s many subsidies.

Reporters for The Guardian spoke to one businessman at Milei’s May 23 rock concert/book launch/political rally who called the president’s slashing of transportation subsidies “directly detrimental to my personal activity” yet who still believed “we must finish the economic cleanup — we can’t keep living a lie.”

Milei’s election last year scrambled the conventional wisdom of North American pundits, who assumed populism had to be hostile to free-market principles.

Yet here was an ardent capitalist ascending to power in the land of Juan and Evita Peron, a duo whose big-government economic nationalism was assumed to be a blueprint for the populist right.

For his part, Milei makes no secret of his admiration for Donald Trump — for what he calls Trump’s “fight against socialism” — and posed with him for a photo op at CPAC last February.

Milei’s not the only evidence that populism and libertarianism can be allies instead of enemies, however:

The Libertarian Party recently shocked many anti-populist libertarians in this country by inviting Trump to speak at the LP national convention.

Is this simply a case of outcasts banding together?

Milei and Trump do represent a repudiation of the old leadership class in their countries.

Those leaders were Peronist in Argentina; here, they were Clinton Democrats and Bush Republicans.

Outsiders attacking the political establishment might be expected to have a similar attitude — a rock ‘n’ roll attitude of defiance, ready to shock and offend.

But there are deeper connections between free markets and anti-establishment politics.

The anti-tax movement that kicked off with California’s Proposition 13 in 1978 was a popular revolt that presaged the election of Ronald Reagan in 1980.

The Reagan revolution was born of free-market populism.

Although many intellectuals who now attach themselves to populist causes find economics to be a “dismal science” — one that casts doubt on their power to save the country through policy brainpower — free-market economics suggests many good reasons why voters turn populist.

Inflation, for example, brings free-market theorists and populist voters’ instincts together.

As Milei said in a recent Time interview, inflation “means you lose the purchasing power of the money you have in your pocket, which is theft. In other words, printing money and putting it on the market is theft; it’s counterfeiting; it’s fraud.”

And just as some businessmen who’ve lost their subsidies still back Milei, populist voters in the United States aren’t necessarily looking for handouts.

They want a fair shake, not a New Deal.

“No taxation without representation” is a perfect expression of the populist side of libertarianism and the libertarian side of populism.

The American Revolution wasn’t just about high taxes — which weren’t steep by today’s standards.

It was about the fact that the taxing authority belonged to an elite that wasn’t accountable to the people.

The American colonists didn’t hate King George III, not at first.

But they demanded control over their own economic destiny, for better or worse.

That’s what populists are calling for today — including free-market populists like Javier Milei.

Daniel McCarthy is the editor of Modern Age: A Conservative Review. To read more by Daniel McCarthy, visit www.creators.com