Wherever government extends its tentacles, innovation follows.

To some contemporary technologists, that might sound like a joke without a punch line. But it’s a reasonable description of 19th century America, according to a new working paper by Daron Acemoglu of MIT, James Robinson of the University of Chicago, and Jacob Moscona of Harvard.

The 1800s set the stage for America’s technological dominance and, as the researchers document, in that era invention and government expansion went hand in hand.

The paper presents a novel dataset for measuring government expansion. “The 19th-century U.S. state quickly started forming a huge web connecting the country,” the authors write. “At the center of this web was the post office, created by the Post Office Act of 1792, which soon became the single most important government employer in the first half of the 19th century… The New York Times in 1852 described it as the mighty arm of civil government.”

And so the researchers collected data on the creation of post offices in counties throughout the U.S. in the 19th century, and compared it to patent data from the same period. The authors offer a couple of reasons why a post office could itself increase an area’s innovation. Counties with a post office were exposed to more information and ideas. And filing patents was considerably easier once a post office was present, particularly because patent applications could be sent without paying for postage.

More than that, though, the researchers see post offices as “as a proxy for the general presence and infrastructural power of the state.”

The authors found a correlation between the presence of a post office and the subsequent number of patents issued in a particular county. That relationship remained even after accounting for population and numerous other variables. Moreover, because the patenting burst followed the arrival of a post office, rather than vice versa, the authors argue the relationship could plausibly be causal.

The researchers came to this question after they were asked to discuss an influential new book on American growth by economic historian Robert Gordon.

“We sort of felt what [the book] is missing is a real understanding of how the institutional environment has impacted technological change in the U.S.,” said Robinson. Discussion of American economic growth ignores “the kind of factors that you’d be discussing if you were discussing Africa or Colombia or Argentina,” he said. “Our view is that doesn’t make any sense. The growth in the U.S. is influenced by the same kind of factors.”

Chief among those factors is the quality of public institutions, as Robinson and Acemoglu have documented in prior work.

When we spoke, Robinson cited the 1862 Homestead Act as an example as an example of how important institutions are to economic growth. The law designated hundreds of millions of acres – roughly 10% of the land area of the country – to be claimed by U.S. citizens or those intending to become citizens. That movement west is associated with America’s “frontier” phase of development, but Robinson argues that what set the U.S. apart wasn’t the available land, but the actual enforcement of property rights (at least for eligible homesteaders) that came along with it.

It’s that sort of institutional support that Robinson and his coauthors had in mind when researching post offices and patenting activity. In the U.S. “there is this capacity to enforce the rules, to provide public goods or property rights that doesn’t exist in Colombia or poor countries,” he said.

Today, property rights and post offices aren’t necessarily what Americans have in mind when they debate the merits of expansive government. And, of course, the economic role of the Post Office has been transformed by the internet. But America’s legacy of comparatively effective, democratic institutions helps explain its technological prowess, and there is even evidence that the more expansive modern state continues to boost innovative output today.

“I look at the U.S. from the perspective of developing countries,” Robinson told me. He believes that Americans often underestimate the quality of their institutions relative to other countries. “One of the big secrets of the U.S., historically, is the construction of this immensely capable state.”