At least one reader on a news aggregator website for conservatives recently sniffed that anyone who hates as much as Ann Coulter does should not wear a cross in public. What made that reader’s simmering disapproval boil over was Coulter’s quip to a radio host about how she hates Carly Fiorina with “the hot, hot hate of a thousand suns” because Fiorina has not renounced the idea of birthright citizenship.

Ann Coulter has so much invested in her career as a polemicist that it would be prudent to attribute that remark to her fondness for zingers that other people keep to themselves. In the audio clip involved, she skips quickly past Fiorina to charge Judge Andrew Napolitano with not understanding the purpose or reach of the Fourteenth Amendment. Both of them are Fox News contributors, but Coulter calls Napolitano a “complete moron” with more vehemence than she had for Fiorina, which makes me think that her shot at Fiorina was theatrical rather than revealing. Fiorina learns from her mistakes, and might yet be persuaded to rethink her position on “anchor babies.”

Coulter specializes in the kind of observation that is equal parts aggravating and educational. She talks now about immigration policy because her book, ¡Adios, America!: The Left’s Plan to Turn Our Country Into a Third World Hellhole (Regnery Publishing, 2015) climbed bestseller lists before Donald Trump started sounding like he’d read it.

¡Adios, America! pulls no punches. Astonishingly under-reported crimes described in several chapters called “Spot the Immigrant!” make for tough reading, but as though to balance that lurid detail, headings throughout the book are deliberately irreverent.

Critics who accuse Coulter of being racist are being willfully obtuse: it’s not race that she has a problem with; it’s mealy-mouthed relativism and the people who willfully mistake that lack of spine for open-mindedness. To understand her motivation for writing the book, you have to accept the premise that some cultures are objectively better than others. In Coulter’s words, “America is not ‘a nation of immigrants,’ it is not an ‘idea,’ it was never ‘diverse,’ and ‘diversity’ is a catastrophe.” Each of the clauses in that impertinent thesis runs counter to received wisdom, so it’s fun to watch Coulter unpack those thoughts with the enthusiasm of an armorer distributing weapons to dwarfs and elves while orcs march on their stronghold.

On diversity, Coulter quotes a study from Harvard suggesting that as cultural diversity in an area increases, so too do levels of mistrust between neighbors. Diversity of cultures, in other words, does measurable damage to social cohesion. Louisiana Governor Bobby Jindal might agree, if we take him at his word that “Immigration without assimilation is invasion.”

Dismissing what she calls “PC nonsense” about America being a “nation of immigrants,” Coulter points out that “Even as late as 1990 — a quarter century into [Democratic Senator] Teddy Kennedy’s scheme to remake the nation — half of the American population traced its roots to the black and white populace of 1790.”

Bolstering her case, Coulter notes that “Nearly the entire white population of America from 1600 to 1970 came from a geographic area of the world about twice the size of Texas,” and “The entire black population came from an area of West Africa about the size of Florida.” What that means, she writes, is that “Until Teddy Kennedy struck, America was never less than 99 percent white Western European and West African black. That’s ‘bi-racial,’ not ‘diverse,’ [because] African-Americans are every bit as much a part of Anglo-Saxon America as the Anglo-Saxons themselves.”

If you guessed that Coulter has contempt for the legacy of the late Senator Edward “Ted” Kennedy, you would be right. She traces much of the current fix we are in to legislation that he championed (and very possibly lied about) in 1965. Four generations later, Coulter says, “The United States is being artificially transformed into Latin America solely for the benefit of Democrats and businessmen in need of cheap labor.”

A hundred pages later, that criticism is reformulated as “This is what Democrats and Marco Rubio are trying to do to our country: Bring in the depraved cultures of the Third World and pretend we’re changing them, rather than them changing us.” And not just us, Coulter says, but our national parks, too. Litter and larceny have spiked on public land, she writes, because the U.S. Forest Service is outgunned, and because there is no cultural foothold south of the border for woodsmanship of the kind summarized by the “take only pictures and leave only footprints” ethos.

That said, it would be ridiculous to think that Coulter has any particular animus toward Mexicans. The 9/11 terrorists were immigrants, and she doesn’t like them, either. Coulter also maintains that every single immigration category tracked by our government is riddled with fraud. While summarizing evidence for that contention, she notes that “In 2008, the State Department suspended the family reunification part of the African refugee program because DNA testing showed that only 20 percent of ‘family members’ were actually related.”

Have progressive critics accused Coulter of “othering”? In her hands, “othering” is not just for breakfast anymore — it comes with statistics, and 90 pages of footnotes for anyone who wants to check her homework.

While more than a few pundits have discussed the impact of unfettered immigration on social services and welfare case loads, Coulter adds in-depth criticism of the tycoons who profit from current policy, chief among them Carlos Slim, the billionaire who bankrolls the New York Times and uses his telecommunications monopoly to profit from wire transfers of money into Mexico.

¡Adios, America! is a depressing but necessary read, marred only by the little bit of research that Coulter did not do. By that I mean that while Coulter’s infatuation for WASP culture is understandable, it sometimes combines with her reflexive sarcasm to make otherwise sound arguments more vulnerable to rebuttal than they should be.

Coulter cannot credibly be accused of “know nothing” nativism, but it would be fair to say that by celebrating allegedly Puritan virtues like temperance and hard work, she forgets that the same virtues were celebrated, for example, in medieval monastic estates long before Puritans came along.

To put the criticism differently: I have no problem with Coulter wearing a cross in public, but she ought to know a little more of its history. There are readers who would finish a book like this thinking that the hard times on which the “Protestant work ethic” has fallen are symptoms of a conflict between religious worldviews that broken immigration policies only manage to aggravate. To follow that rabbit down that hole, however, you have to ignore significant changes in the Latin American religious landscape. Coulter could have added a page or two to make that clear, and it’s a pity she did not. Nevertheless, her new book is decidedly worth reading.