Emmett Till is shown lying on his bed.Bettmann / Getty

What does American tyranny look like? In the past few months, fears about the collapse or degradation of the American democratic system have led many to engage in the grim exercise of game-planning the endgame of tyranny. For some, dystopian novels ground that exercise. Some take stock of the rise of authoritarian powers in the past. Others rely on expert realpolitik analysis from political minds like my colleague David Frum. Regardless of the source, we have arrived at Belshazzar’s feast. The writing is on the wall: It could happen here.

Or, it could happen here again. After all, it wasn’t too long ago in American history that millions of Americans were trampled under the heel of a repressive, anti-democratic kleptocracy and faced economic reprisals, violence, or death for any dissent. And nowhere was the iron grip of that system—known as Jim Crow to some of us—stronger than in Mississippi. That grip manifested itself most notoriously in the murder of Emmett Till, a 14-year-old black boy, in 1955. That year, Till was tortured and lynched by white men after allegedly making lewd comments toward a white woman. His mutilated corpse became one of the first mass-media images of the violence of Jim Crow, and the trial of his killers became a pageant illuminating the tyranny of white supremacy. And through protests across the country, Till’s broken body became a powerful symbol of the civil-rights movement.

In his new book, The Blood of Emmett Till, the historian Timothy B. Tyson revisits the circumstances of Till’s death, and brings to bear a wide scope of reporting, historical research, and cultural analysis. It’s not a definitive history of the Till case; other works have synthesized more primary sources and firsthand accounts. Rather, The Blood of Emmett Till is focused on the historicity of race in America: It posits that Till’s death is an emblem of the ways in which American tyranny works. To that end, the climax of his book comes not in the death of Till, in the ensuing sweltering court proceedings, or in the backwoods thriller of the black Mississippi Underground that investigated the case, but in the present.

Tyson tells the story of how a young Chicago boy’s summer sojourn in Mississippi ended with him kidnapped, beaten, shot, and tossed into a river by Roy Bryant, J.W. Milam, and a group of others. The historical context Tyson provides often dwarfs the actual tick-tock of the case: An account of Mamie Till-Mobley’s childhood and her close bond with her son is wrapped in a narrative about the Great Migration of black people from the South to the West and North in the mid-20th century. Till’s lynching is backgrounded by an instructive history of the genteel and intellectually racist Citizens’ Councils and how they fueled the raw violence of a white proletariat. The surfeit of contextualization verges on digression at times, but serves the ultimate purpose of giving Till’s life weight six decades after his death.

The effect of Tyson’s wide-angled framing is especially pronounced in the bombshell revelation that Carolyn Bryant—the white woman who originally claimed Till grabbed and sexually harassed her in her husband’s store—lied about those claims. Media coverage has focused on that explosive admission and the conversation around redemption that it seems to spark, but Tyson’s book, in the end, is largely unconcerned with that line of inquiry. Bryant’s testimony on the stand and her later admission have little to do, in this narrative, with her own battle with guilt; rather, they serve to advance Tyson’s thesis that culpability for Till’s death rests on millions of shoulders. The unlikely thing, he argues, was not that Emmett Till was lynched, but that his lynching actually stirred a national response.

Tyson takes great pains to illustrate how the mechanisms working in Jim Crow Mississippi in 1955 still animate life today, and how America has never really found justice for Till. He details the rise of the civil-rights movement and how Till’s death helped to forge a common purpose for the wide-ranging and often contentious factions of black activism. He describes how white supremacist organizing arose in direct response to that mobilization. And he examines how school desegregation and black suffrage undergirded the social tensions of the Jim Crow era.

Perhaps most importantly, Tyson considers all the ways in which an American populace was complicit in its acceptance of violence against black people—and then considers all the ways in which it is still complicit in the deaths of people of color today. For instance, in his examination of the Citizens’ Councils’ literature, which fomented mass fears of black criminality and fantasies of rampant black sexual deviancy, Tyson also shows how poor white “peckerwoods” were loathed by wealthier white people, and manipulated into doing the bloody business of physical violence. In this, he provides a thinly veiled parable for today’s politics in how the rhetoric of white supremacy—even in its subtlest dog-whistle form—is used to radicalize people, and how the uneasy detente between classes of white people is often maintained by propaganda built around the threat of the other, even as the culpability is passed to the lowest rungs. “We blame them,” Tyson writes about those radicalized perpetrators of physical violence, “to avoid seeing that the lynching of Emmett Till was caused by the nature and history of America itself and by a social system that has changed over the decades, but not as much as we pretend.”

In service of his analysis of the present, Tyson also compares the “Emmett Till generation” of civil-rights leaders that developed after Till’s death to the Black Lives Matter movement that gathered force after the killings of Trayvon Martin and Michael Brown. In The Blood of Emmett Till, that comparison is not just a coincidence, but, rather, the end result of a social system that continues to perpetuate injustice today. “America is still killing Emmett Till,” Tyson writes, “often for the same reasons that drove the violent segregationists of the 1950s and 1960s.”

The Blood of Emmett Till is a critical book not just because it provides a good reason to revisit a foundational moment in American history—though it manages that feat in spades—but also because it manages to turn the past into prophecy and demands that we do the one vital thing we aren’t often enough asked to do with history: learn from it. In firmly tying Till’s legacy to protests over black bodies, re-segregation, voting-rights struggles, hate crimes, and the creeping reemergence of bigotry today, Tyson implores readers to learn that American tyranny already has a face, has already left millions of victims in its wake, and doesn’t take a whole lot of imagination to fathom. Perhaps the dystopia we envision isn’t some far-off future, but simply a return to the past.