Contemporary fictions set in future dystopias tend to reflect liberal anxieties, such as climate change or the corporate takeover of our public institutions. Lionel Shriver’s 12th novel is something very different.

“The Mandibles: A Family, 2029-2047” approaches the imminent collapse of American society from the right side of the political spectrum. As it opens, entitlements have driven the national debt to unsustainable levels, making the dollar worthless. Expansionist Keynesian economists are proved to be a “gang of charlatans.” A desperate nation renounces its debts, foreign and domestic. To refill the treasury, the federal government confiscates citizens’ gold, right down to their wedding rings.

“The Mandibles: A Family, 2029-2047" by Lionel Shriver (Harper)

This would be refreshing, as dystopias go, if Shriver’s novel wasn’t so burdened with dialogue in which the characters repeatedly explain to each other the reasons for America’s calamitous fall. They’re really lecturing the reader, of course, their main themes being initiative-sapping big government and the frauds perpetuated by the Federal Reserve.

The novel’s principal lecturers are members of the extended Mandible family who, as the crisis deepens, teach us the real-world consequences of easy money. One works in a homeless shelter; others include a writer, a therapist and a Georgetown economist. They’ve been waiting for their inheritances to trickle down from Great Grand Man Douglas Mandible, whose own grandfather made the family fortune manufacturing diesel engines. But at 97, Douglas is still playing tennis on the grounds of his fancy retirement home.

After the 2029 crash, not only does the fortune vanish, the once-dashing, imperious Great Grand Man gets evicted. He and his dementia-impaired second wife, Luella, have to move in with his son in a rapidly de-gentrifying Brooklyn. Other Mandibles lose their homes, too. The family’s fortunes go from bad to worse to indigent while they squabble among themselves, trapped in a country whose economy has shut down.

The decline is steady and the novel can go hundreds of pages with hardly a plot turn — or a joke — but Shriver keeps the story moving by shifting its focus among the Mandibles. One fully voiced character is Douglas’s granddaughter, Florence, the shelter worker and a single mom, whose liberal confidence in the social order is confounded by the awfulness of her neighbors under stress. The crime rate soars. “Late in the day, she appreciated the miracle of civilization, whereby people paraded sacks of grocery, or jingled keys to a car, and were not immediately set upon.”

The Mandibles go hungry amid the ruins of an America that hasn’t been made great again, and it’s clear who the culprits are. Becoming bluntly partisan, the novel uses fantasy and name-checks to score points against Florence’s fellow liberals in her time and ours. The immigration amnesty of 2020 is followed by a constitutional amendment that allows for a foreign-born president: a pudgy, lisping Mexican, just one of the novel’s several racist characterizations. The criminally incompetent Fed chairman is named Krugman. Later, some very bad stuff goes down during the Chelsea Clinton administration.

The grinding poverty at least strengthens the nation’s moral fiber: “They had now entered a hard-assed era of American culture,” Shriver writes, “during which all that gutless guff about ADHD, gluten intolerance, and emotional support animals was out the window.”

The Mandibles are white. Luella, the single African American in the family, arrives in Brooklyn incontinent and demented. She needs to be physically restrained. As their fortunes become ever more dire and the family assembles for a perilous trek through the streets of lawless New York, she’s held at the end of a leash. If “The Mandibles” is ever made into a film, my suggestion is that this image not be employed for the movie poster.

Author Lionel Shriver. (Sarah Lee)

At times, Shriver’s novel reads like the “FoxLiberty-Ultra” version of Gary Shteyngart’s “Super Sad True Love Story,” without the humor, but it more often recalls the libertarian fables of the classic science fiction writer Robert A. Heinlein. Further in the future, when active workers are slaves whose labor funds Social Security, one Mandible educates the other in the inevitable depredations of the state: “Government becomes a pricey, clumsy, inefficient mechanism for transferring wealth from people who do something to people who don’t, and from the young to the old — which is the wrong direction.” This analysis, reductionist in its language and its vision, echoes the lessons of Heinlein’s “The Moon Is a Harsh Mistress” (1966).

Shriver is, nevertheless, an engaging writer. Even with their speechifying and the tediousness of the story, her characters solicit your sympathy, much more than they usually do in genre science fiction. And also, as in good science fiction, you often have to look up from the page to remind yourself that you don’t live on the planet that’s being described.

You don’t and you won’t. The dollar isn’t a fraudulent, doomed concept. Americans aren’t the weak, pliant, feckless people portrayed in “The Mandibles.” True, some days the news intimates that we already live in a dystopic future, an apocalypse located in far-off 2016, but we’re still a nation that to a reasonable extent controls its destiny. Whether science fiction or not, literature set in the future suggests that we can still choose among our possible tomorrows. Some of these tomorrows will be happier than others.

Ken Kalfus’s latest book, “Coup de Foudre: A Novella and Stories,” has just been published in paperback.

A Family, 2029-2047

By Lionel Shriver

Harper. 402 pp. $27.99