One lesson of the U.S. presidential election is that we should forget about red and blue states, North and South, coastal coffeeshops and heartland diners. The geographic divide in American politics is closer to home. If you want to predict how someone will vote, ask, How near are your neighbors?

Residential density has long played a role in shaping American politics. In the recent election, 49 of the 50 highest density counties voted for Hillary Clinton, and 48 of the 50 lowest density counties chose Donald Trump (nearly the same split as for Barack Obama and Mitt Romney four years earlier). In “blue” California, the agricultural towns of the Central Valley swayed Republican, while in “red” Texas the big cities voted Democratic. Across the spectrum of purple hues, a high-resolution map of population density closely matches voting results.

There are reasons for this that go beyond identity politics. Urban density has social and economic advantages that make cities attractive to liberals and that also condition liberal values over time. Living among diverse neighbors can reduce fear and resentment, as everyday interactions break down stereotypes and misconceptions of ‘the other.’ (Which is not to ignore that cities have their own problems with racial and economic segregation.)

One recent study compared voters who switched from Obama to Trump with those who switched from Romney to Not-Trump. Controlling for “age, race, education, income, gender, party identification, concern about rising immigration, racial resentment, and worries about personal finances,” the authors found that a vote for Trump was correlated with fear of rising diversity. They concluded that the election was a “clash over the openness of society,” which may explain why cities produce liberal voters. Density politics is arguably at the core of racial acceptance.

Or, as The Stranger put it, two weeks after the election:

Look at the faces of the people sitting with you in the cafe, or bar, or free clinic lobby, or library. Look across the aisle of the bus, or subway, or light rail train you’re riding. Look at the drivers stuck in freeway traffic with you. Look at the young and old of all colors and creeds who share this city with you, some sleeping, not far from you, under tarps and highway overpasses. This is the American city. You are fortunate to be here, inside one of the most powerful machines we have for defeating fascists.

Understanding the relation between space and politics is now a basic requirement for civic literacy. Can the typical American voter tell you how dense her or his community is? How land, housing, and infrastructure are organized at different scales? To illuminate this, my office examined the relation between density and the popular vote across all 3,144 counties. We then illustrated 51 counties, representing a range of geographic locations and political affiliations, to understand their varied spatial organizations. So rarely are the spaces in which we live depicted when Americans discuss politics. We wanted to show that landscapes are not neutral, that they reflect social and economic relationships that shape (and are shaped by) our politics.

In counties that voted overwhelmingly for Clinton, households are 215 feet apart on average; in strong Trump territory, they are nearly half a mile distant.

If you live in a Clinton stronghold, one of the 11 counties which the Democratic candidate won by a margin of 70 points or greater, the average density is about 2.1 people per acre. That includes high-density Manhattan, the Bronx, San Francisco, and Washington, D.C., but also rural counties in Mississippi and part of the Pine Ridge Indian Reservation in South Dakota. If you were to distribute those households evenly, sprinkling New York apartments through the Badlands, you would have neighbors 215 feet in every direction.

Conversely, there are 201 sparsely populated counties that Trump won by a margin of at least 70 points. If households in Trump country were evenly spaced, they would be 2,412 feet apart — nearly half a mile. The tipping point, where the two candidates split the vote, is a hypothetical county where neighbors live 608 feet apart.

These drawings were inspired by the biologist-geographer Patrick Geddes who, in 1909, argued that physical environments shape human activity, and that people, in turn, act on environments through their labor. Geddes drew a geographic section that moves from mountain to foothills, through plains and riparian edges, down to the water. In each of these settings, Geddes identified the most adapted forms of labor and tools, from the miner’s pickaxe to the fisherman’s net, believing that “the kind of place and the kind of work done in it deeply determine the ways and institutions of its people.” For Geddes, our lifestyles, and therefore our politics, emerge from negotiation with the environment.

A half century later, a group of young architects affiliated with the breakaway CIAM group Team X published the Doorn Manifesto, which updated Geddes’s valley section to show corresponding dwelling types. Team X contended that housing should be conceived as habitat, a negotiation of local circumstances, environment, and social relationships. Their “scales of association,” from city to town, village, and farm, matched density to particular social relations and patterns.

Today, many geographers, planners, and designers understand density on a continuum. There is no clean line between city, suburb, exurb, town, region, and hinterland; there are only multifaceted, networked territories. Our drawings aim to update the valley section to probe the relationship between environment and density politics. We still do not have adequate language to fully describe all these landscapes, but we can examine their spatial characteristics.

It’s remarkable that even as the internet disperses information and enables us to form online communities across great distances, our politics are still highly correlated with physical environments. Who we are is largely defined by where we are. For architects and urban designers, this is an important reminder that space is and always has been political, from the days of the valley section to the postmodern stage of Trump.