Jim Tankersley, The Washington Post

In the modern era of presidential politics, no candidate has ever won the popular vote by more than Hillary Clinton did this year, yet still managed to lose the electoral college. In that sense, 2016 was a historic split: Donald Trump won the presidency by as many as 74 electoral votes (depending on how Michigan ends up) while losing the nationwide vote to Clinton by 2 million votes and counting.

But there’s another divide exposed by the election, which researchers at the Brookings Institution discovered as they sifted the election returns. It has no bearing on the election outcome, but it tells us something important about the state of the country and the future of its politics.

The divide is economic, and it is massive. According to the Brookings analysis, the fewer-than-500 counties that Clinton won nationwide combined to generate 64 percent of U.S. economic activity in 2015. The more-than-2,600 counties that Trump won combined to generate 36 percent of the country’s economic activity last year.

Clinton, in other words, carried nearly two-thirds of the American economy.

With the exceptions of the Phoenix and Fort Worth areas, and a big chunk of Long Island, Clinton won every large-size economic county in the country.

This appears to be unprecedented, in the era of modern economic statistics, for a losing presidential candidate. The last candidate to win the popular vote but lose the electoral college, Democrat Al Gore in 2000, won counties that generated about 54 percent of the country’s gross domestic product, the Brookings researchers calculated. That’s true even though Gore won more than 100 more counties in 2000 than Clinton did in 2016.

Between those elections, U.S. economic activity has grown increasingly concentrated in large, “superstar” metropolitan areas such as Silicon Valley and New York.

But it’s not the case that the counties Clinton won have grown richer at the expense of the rest of the country – they represent about the same share of the economy today as they did in 2000. Instead, it appears that, compared with Gore, Clinton was much more successful in winning over the most successful counties in a geographically unbalanced economy.

The Brookings analysis found that counties with higher GDP per capita were more likely to vote for Clinton over Trump, as were counties with higher population densities. Counties with higher shares of manufacturing employment were more likely to vote for Trump.

“This is a picture of a very polarized and increasingly concentrated economy,” said Mark Muro, the policy director at the Brookings metro program, “with the Democratic base aligning more to that more concentrated modern economy, but a lot of votes and anger to be had in the rest of the country.”

As Muro notes, many state legislatures are divided on similar grounds, between higher-output metro areas and lower- output rural ones. Often, that divide pushes governors of those states, even the ones who hail from cities, to support economic development in lower-output areas. Such a dynamic could be an upside under a president who won votes representing only a third of the country’s economy: To respond to his voters, Trump could promote policies to help those areas adapt more rapidly to the changing economy.

There’s a downside, though, for a candidate such as Trump, whose economic appeal was rooted in a promise to restore coal, manufacturing and other jobs lost in the shifts of the past several decades.

That task will be difficult, Muro has written, in part because manufacturers have grown substantially more productive in recent years, meaning they probably won’t be adding millions of workers even if Trump pursues major changes in trade policy that result in more goods being made in the United States.

“The prescription isn’t that helpful,” Muro said. “We’re going to have a lot of questions about how to translate the political geography into actually helpful policy.”