In a world where #BlackLivesMatter has become an existential argument, it's an unspoken truism among people of color: White people will kill to protect their position atop the social order, especially if they feel threatened by people who aren't white.

In his remarkable new book, "Dying of Whiteness: How the Politics of Racial Resentment Is Killing America's Heartland," Jonathan Metzl argues they're willing to commit suicide, too — and the primary means of self-destruction is the ballot box.

His thesis: Conservative whites who hate taxes, gun control and government programs such as the Affordable Care Act are guzzling an elixir that Republicans say will Make America Great Again. But instead of restoring a mostly white (and largely imaginary) era free of rap music and Spanglish, Metzl writes, the toxic brew is shaving years from those voters' lives, damaging their health in measurable ways.

Dividing into case studies, "Dying of Whiteness" examines three political issues with broad support among white voters: expansion of gun rights in Missouri after the #BlackLivesMatter protests in Ferguson; Tennessee's decision to opt out of Obamacare; and former Gov. Sam Brownback's fiscally bloody tenure in Kansas — the GOP "experiment" that promised boom times after to-the-bone tax cuts.

Politicians sold those policies as safeguards against criminals, moochers and Big Government, Metzl writes, but the intended effect — punishing and endangering the health of poor minorities, choking off taxpayer-funded institutions that help them and helping to calcify institutional racism — is barely disguised. Through field interviews, research and public-health data, Metzl shows that whites are harming themselves along with everyone else, and in drastic ways.

Slashing Missouri's already lenient gun-control laws unleashed a dramatic spike in white male gun-related suicides there. In Tennessee, one of several red states that rejected Obamacare, mortality and preventable-disease rates ticked up among poor whites when the Volunteer State turned its back on the program, leaving billions of dollars in health care subsidies on the table.

Kansas' radical tax-cut experiment crippled its economy and its once exemplary public school system, pushing up class sizes and dragging down graduation rates for white students.

The cut-your-nose-off harm that whites are doing to themselves, Metzl writes, is hard to see but impossible to miss when you crunch the numbers. It's the self-destructive price, he adds, of protecting "an imagined place atop the racial hierarchy — that is, an investment in a sense of whiteness."

As a physician and psychiatrist reared in the Midwest, Metzl has science and Heartland street cred on his side; as a public health instructor at Vanderbilt University School of Medicine, his clinical approach doesn't overshadow his skill as a wordsmith. As a result, "Dying of Whiteness" is a weighty but smooth read, devoid of polemics or jargon.

While the results of Metzl's epidemiological study aren't all that surprising to those of us with brown skin (and others who yelled at the TV during the last presidential election), the good doctor writes without judgment. That's despite some of his subjects who cling to paranoia despite personal circumstances: people who lost loved ones to gun suicide but reject gun control; chronically ill Medicaid patients who argue that the nation can't afford subsidized health care; tax cut-loving suburban parents shocked to find that their kids now experience the same appalling classroom conditions common in poor urban districts.

As a result, reading "Dying of Whiteness" brought a quote attributed to the civil rights activist, educator and scholar Booker T. Washington:

"To keep a man down," he said, "you have to stay down with him."

Joseph Williams is senior editor for U.S. News & World Report in Washington, D.C., covering the Supreme Court and national politics.

Dying of Whiteness
By: Jonathan M. Metzl.
Publisher: Basic Books, 341 pages, $32.