The central premise of “American Whitelash” is that “each step toward a more racially just society, each step toward triumph gained by the anti-racist side of the struggle, each periodic collection against the unfulfilled pledges of the American promissory note, in turn, sparks a backlash — a pull back on the rope — from the unjust system’s beneficiaries and boosters.” Whitelash, then, takes on different and historically specific forms as Whiteness expands to “accommodate waves of new members” and contracts to exclude formerly secure constituents. Italian Americans, now comfortably assimilated, faced brutal whitelash in the early 1900s — and, as Lowery has frequent occasion to remind us, the inclusion of Ashkenazi Jews as White is still contested, often bloodily, by neo-Nazis.

Lowery’s book is not a comprehensive history of White resentment in America — such a study would surely be many times as long — but an incomplete examination of the most recent wave of hatred and recrimination. It begins on the eve of Barack Obama’s election, when the air was laced with optimism that seems naive in retrospect. For one thing, Lowery writes, Obama’s presidency revealed the shortcomings of the “‘black faces in high places’ politics that had taken hold in the decades since the civil rights movement.” Far from representing a radical break with American politics as usual, the 44th president “hedged and stood tall in two-sides-ism,” as the poet and essayist Camonghne Felix observed in an essay from which Lowery quotes.

Even worse, Obama’s election infuriated and emboldened the country’s most poisonous reactionaries: “At least two prominent white supremacist organizations — Stormfront and the Council of Conservative Citizens — saw their websites crash due to the flood of online traffic that came their way following Obama’s victory.” An uptick in racially motivated hate crimes soon followed. No wonder the president who assumed office in 2016 was the white supremacists’ candidate of choice.

Lowery explains that criminologists sort perpetrators of racial violence into three categories: “thrill-seekers,” like teenagers who use epithets in an effort to shock and provoke; “reactive attackers, who lash out suddenly at perceived enemies such as immigrants or LGBTQ people”; and “mission-oriented attackers, the avowed ideologues who carry out calculated attacks.”

“American Whitelash” focuses almost exclusively on lone wolves in the second category. Four of the six incidents it chronicles at length occurred during the Obama administration, two during Trump’s. This distribution is as instructive as it is unexpected: Even during the apparently (to a certain kind of blinkered liberal, anyway) halcyon days of the Obama presidency, dark forces were at work. A teenager who had been radicalized by white supremacists online stabbed an Ecuadoran immigrant on Long Island in 2008; a veteran skinhead opened fire at a Sikh temple in Oak Creek, Wis., in 2012; an outspoken neo-Nazi committed a mass shooting at a Jewish community center in Overland Park, Kan., in 2014; and white supremacists took up arms against Black Lives Matter protesters in Minneapolis in 2015.

In light of these antecedents, the two episodes in the book that transpired after 2016 — the notorious rally in Charlottesville in 2017 and a racially motivated murder in Maryland in 2017 — come to seem like continuations, even culminations.

Lowery writes that his book is “an attempt to put human faces on the relentless cycle of violence that has defined American history,” and the attempt succeeds. He is a lively narrative reporter with a keen eye for detail, and his prose can be devastatingly vivid. The mother of Oscar Grant, a Black man shot by the police in Oakland, Calif., in 2009, crouched over her son’s hospital bed and “tried to talk him out of dying.” When the father of a Black man stabbed by a white supremacist saw state troopers approaching his house, his “heart sank to his waist.”

But when Lowery moves from narrative to conceptual territory, he is on shakier ground. “A central question during the years that followed the 2008 election was how much the era’s racially inflammatory rhetoric was inciting — or, at the very least contributing to — those acts of racial violence,” he writes. A second core conundrum concerns “how to balance the rights of most Americans — even American racists — to free speech and free expression with the government’s sacred responsibility to ensure the safety and security of the rest of society.” In other words, how do we weigh our interest in preventing hate crimes against our interest in restricting the state’s ability to monitor the populace (particularly given that the biggest expansion of the American surveillance apparatus in recent memory disproportionately targeted people of Middle Eastern origin)? These are thorny and vital questions — but although Lowery repeatedly raises them, he never ventures answers.

More frustratingly, “American Whitelash” contains little contextualization that might help us relate horrific but uncommon acts of extremism to the mundane mechanics of racism — to mass incarceration, to income inequality, to voter suppression, to White flight, to police brutality. We never learn exactly how pervasive neo-Nazism has become in America or how often full-fledged fanaticism springs out of, or shades into, the more quotidian but equally (if not more) harmful brand of bigotry practiced by a much broader swath of White Americans. The political philosopher Tommie Shelby has pointed out that even well-meaning people can “perpetuate oppression” by performing actions that impose “an unnecessary, systemic, and undeserved burden” on another group of people — actions that “have this result whether or not they are performed with a racist heart.” How we feel matters less than how we structure the world. Personal atonement is not an adequate solution to patently public problems.

If the issue at stake is whitelash — defined as “a pull back on the rope” from “the unjust system’s beneficiaries and boosters” — then the phenomenon’s most harmful incarnations are not dramatic but bureaucratic. Gerrymandering and mass deportations of undocumented immigrants, both of which proceeded apace during Obama’s presidency, can be more broadly consequential than hate crimes, at least in terms of scale. As usual, the less theatrically evil villains are all the more chillingly effective.

Becca Rothfeld is the nonfiction book critic for The Washington Post.

A Changing Nation and the Cost of Progress