For the past 80 years, the United States has led the world in scientific research. In retrospect, that dominance might seem inevitable. But it wasn’t.

Two hundred and fifty years ago, American science barely existed. Benjamin Franklin had an international reputation. But he was an outlier. Europe was where the real work was happening — with German universities, French academies and British laboratories at the cutting edge.

The peripheral status of the U.S. persisted well into the early 20th century. “If you look at the nation around 1900 or so, it was still a scientific backwater,” says historian Peter Westwick.

What changed? First came investment. The Morrill Act of 1862, signed by Abraham Lincoln in the midst of the Civil War, created the land-grant universities. Then Gilded Age philanthropists, such as John D. Rockefeller and Andrew Carnegie, poured money into institutions modeled on the German research university. By 1900, physics funding in the U.S. was expanding twice as fast as in Britain or Germany. In 1932, the U.S. had three times as many physicists as in 1919.

Then came an influx of world-class scientific talent. Scientists fleeing European fascism, such as Germany’s Albert Einstein, Italy’s Enrico Fermi and Hungary’s John von Neumann, boosted what homegrown investment had begun. From 1945 to 1984, a third of all U.S. Nobel laureates in science were born overseas. The 1965 Immigration Act ushered in another wave of talent, channeling global expertise into universities and Silicon Valley. By the late 1990s, immigrants were leading a quarter of the region’s tech firms.

The final piece of the puzzle fell into place during World War II with the launch of the federal research contract. The Manhattan Project mobilized entire universities, establishing a model that extended through the Cold War and into biomedical research via the National Institutes of Health. That infrastructure still underpins American science today.

For Westwick, professor of the practice of thematic option and history, the story of America’s transformation from scientific backwater to research powerhouse should serve as a warning against complacency. No nation, he points out, has led global science indefinitely. In the 16th century, the Italian city states dominated. Britain surged ahead in the 17th. France led in the 18th, and Germany took over in the 19th.

“We tend to assume that American scientific leadership is somehow inevitable,” Westwick says. “But in fact, it is a relatively recent historical phenomenon — and most likely a temporary one.”

As federal funding shrinks and pathways for international talent narrow, the question now, Westwick notes, is whether the U.S. can sustain what took a century and a half to build.