In the early hours of April 3, 2019, in a tableau that many Americans will recognize, the darkness of my family’s New York apartment was ruptured by the contemptible light of a laptop. An election result in another time zone had kept me up. In the race for a Wisconsin Supreme Court seat, Brian Hagedorn, a man so extreme in his views that he’d alienated reliable conservative donors, had beaten his moderate-liberal opponent, the chief judge of the Wisconsin Court of Appeals, Lisa Neubauer. This wasn’t just bad—this was worrying.

Our polarized national politics means that the Presidential election is exceptionally transparent. If the Democrat flips Michigan, Pennsylvania, and Wisconsin, he or she will almost certainly win. If Donald Trump holds just one of these states, he will very likely scrape together an Electoral College majority. In the 2018 midterms, which came to be known as the Blue Wave, Democratic gubernatorial candidates won in Pennsylvania and Michigan by about seven points. In Wisconsin, the Democrat Tony Evers defeated Scott Walker, the incumbent governor, by a point—fewer than thirty thousand votes. If the upcoming Presidential race goes down to the wire, it very much looks like the wire will be in Wisconsin.

How had Hagedorn won? Trump had carried the state by only twenty-three thousand votes. Neubauer’s supporters had spent a fortune on her campaign. Elections around the country were trending against the G.O.P. How had Wisconsin Republicans overcome all of that? As Butch Cassidy might have asked: Who are those guys?

They’re WOW voters, I learned online. The suburbs of Milwaukee in Waukesha, Ozaukee, and Washington counties are heavily white and legendary in political circles for delivering victories to the G.O.P. While suburbs elsewhere in the country have turned away from the Republican Party, WOW came through for Hagedorn. His win confirmed my worst nocturnal fears: Wisconsin conservatives know how to win elections.

Most Democrats in Wisconsin are concentrated in two cities: Madison and Milwaukee. Voter turnout in Madison has been consistently very high; in Milwaukee, it has been up and down. In the 2012 Presidential election, Milwaukee city’s turnout was measured at sixty-six per cent, but in 2016 it fell to fifty-six per cent. The difference comes to forty-one thousand votes—almost double Trump’s margin of victory.

This is not the whole story, of course. But even I, who had never set foot in the state, could figure out this much: if Milwaukee voters turn out in numbers, Trump will be in trouble. Who are those guys?

Here we come to one of the great historical ironies of the 2020 election. Milwaukee has been rated the worst city in the country to be an African-American resident, yet nearly forty per cent of its population is African-American. What may be the most downtrodden urban community in the United States has a superpower: the potential to decide who will be the country’s next President.

On a cold, gray, intermittently sleety afternoon in December, I accompanied three young women as they knocked on doors on West Galena Street in Milwaukee. The women, who wore name tags identifying them as Tamer, Amari, and Brittany, literally knocked: doorbells were not put to use. Some of the doorknobs had tags on them, hung by other visitors, stating “Fight for $15 and a Union.” The women visited some thirty homes and were answered five times, not counting numerous barking dogs. They delivered pamphlets and engaged three residents in meaningful conversation. They got two signatures for a petition—for Unlock the Vote WI, a campaign to restore voting rights to formerly incarcerated Wisconsinites. Tamer Malone, Amari Rucker, and Brittany Ezell were civic ambassadors for a group named BLOC—Black Leaders Organizing for Communities.

This part of West Galena Street is on Milwaukee’s North Side. The North Side has connotations that are as much racial as geographic. Milwaukee is perhaps the most segregated metro area in the United States. The North Side is where almost all of its African-Americans live.

If you drive through the North Side’s extensive neighborhoods, you’ll be struck by its green and tranquil appearance. There are parks and grassy spaces, and buildings designed as single-family homes, often sizable and handsome, dominate the housing stock. The portion of West Galena Street where the BLOC ambassadors were canvassing is not atypical. Between the Ultra Food Mart convenience store (“We don’t go in those,” Malone told me, “for our own safety.”) on the block’s southeast corner and the white clapboard Good Way Church, on the northwest corner, were sizable old houses separated by large, grassy yards. Apart from a few people milling around the convenience store, the street was quiet. You’ll see some boarded-up or fallen-down properties in north Milwaukee and notice a distinct lack of retail activity. Sometimes a car drives by that hasn’t been fixed up since its last crash. But unlike, say, parts of Detroit or Baltimore, Milwaukee does not offer a spectacle of urban ruin.