This isn’t the first time a leader has promised an economic golden age ushered in by tariffs. It’s been promised before and it’s been tried before.

“Import substituting industrialization was a development strategy that was extremely popular in developing countries for about 35 years after World War II,” explained Paul Krugman, professor of economics at the City University of New York and Nobel Laureate.

Many countries during this period felt an urgent need to recreate the industrialization they saw in Europe and the U.S., and the Great Depression had pushed countries to look inward.

“Every time you have conflicts or you have trade disrupted, in the mind of the leaders and in the mind of the people is the idea that, well, we cannot trust to get everything through trade,” said Sebastian Galiani, professor of economics at the University of Maryland and former deputy finance minister of Argentina.

Newly independent former colonies embraced this too. In a famous speech to the Organization for African Unity in 1963, Ghanaian prime minster Kwame Nkrumah called for economic independence: “It is impossible to think of economic development and national independence without possessing an unfettered capacity for maintaining a strong industrial power.”

The way to do this, many believed, was to wall their economies off from imports.

“It was the idea that you will put on tariffs, other kinds of restrictions on imports,” said Krugman.

Why buy from abroad when you can make it at home, creating manufacturing or industrial jobs and accelerating the development of the country along the way, the rationale went.

“The rhetoric in many ways resembled what Trump is saying,” said Krugman, “although there was never any talk about Make Brazil Great Again, because Brazil hadn't been great. Brazil was a poor country that was trying to make it a little bit richer.”

Behind a wall of tariffs and other barriers, countries would “build up an industrial sector … and then supposedly it'll become efficient and will no longer need the barriers once it's matured. So you saw that followed everywhere, from India to Brazil.”

Many countries raised tariffs again and again, Argentina among them.

“At some point they were on average 200%, so that’s … really high,” said Galiani. But something happened when the tariff wall went up: stagnation.

The industries that emerged were competitive only inside the bubble of Argentina. They were not advanced.

“Let me tell you a story about toys,” said Galiani. “When I was, I don't know, let's say seven and eight years old [in the ‘70s], my father was an important producer of shoes in Argentina. And he goes to Europe twice per year, and so he always brought me back toys from Europe.”

On one occasion, he brought back a Big Ben clock toy — “state of the art” from Paris.

“And there’s a guy that wants to copy them in Argentina under protection,” he said. He asked if the young Galiani would hand over his toy to be broken apart so it could be copied, but the man offered Galiani three of the versions he would make.

“And I say fine, take mine and you give me three — I can tell you the three he gave me didn’t pay — he needed to give me 100 to compensate me, what he produced was so bad!” Galiani recalled with a laugh.

Being cut off from trade made economies less efficient and less innovative. This pattern repeated itself.

“A good country example here would be India,” said Doug Irwin, professor of economics at Dartmouth College. India produced a car known as the Ambassador, “which was basically the same in the 1970s as it was in the 1950s — it looked the same. They didn’t really improve the quality of the product.”

He said living behind a tariff wall saddled the country with a large manufacturing sector that wasn’t internationally competitive and didn’t much improve living standards, “so yes, import substitution can bring about a lot of manufacturing, but whether that’s efficient and adds to the wealth of the nation is another question.”

After three or four decades, governments around the world became disillusioned with this experiment.

“It was not a success story,” said Krugman. “The industries never became efficient, economic growth was really disappointing, and rather rapidly in the 1980s the developing world changed to a strategy of embracing international trade.”

It’s a piece of history, he said, the U.S. could learn from.