The lies rain down on us so relentlessly that we’re often benumbed. Shortly after Donald Trump tweeted last week that the Russians would help the Democrats win the midterms, we learned that the Russians have tried to hack the 2018 campaign of Sen. Claire McCaskill — a Democrat. And minutes after Donald Jr. tweeted that President Obama’s economy never posted 2 percent GDP growth, we learned that Obama had in fact posted 2 percent GDP growth 15 times.

Michiko Kakutani, the Pulitzer Prize-winning literary critic, has posed the questions that often bedevil us: “How did this happen? What are the roots of falsehood in the Trump era? How did truth and reason become such endangered species, and what does their impending demise portend for our public discourse and the future of our politics and governance?” She supplies the answers in her new book, “The Death of Truth,” a bleak treatise that ends with a dose of hope.

Consider this my summer book recommendation. I wouldn’t necessarily take her slim volume to the beach, lest you be tempted to drown yourself. But it’s a bracing read nonetheless, because she writes so concisely and incisively, and because she draws wisdom from so many disparate influences.

You’ll be hard-pressed to find another social commentator who can critique Trump and our corroded cultural-political climate by quoting both Vladimir Lenin (rhetoric should be “calculated to evoke hatred, aversion and contempt…of such a nature as to evoke the worst thoughts, the worst suspicions about the opponent”), and The Joker from Batman (“Introduce a little anarchy. Upset the established order and everything becomes chaos”).

It’s tempting to read Kakutani only for her withering assessment of Trump, if only because it’s so on the mark: “Long before he entered politics, Trump was using lies as a business tool. He claimed that his flagship building, Trump Tower, is 68 floors high, when, in fact, it’s only 58 floors high. He also pretended to be a PR man named John Barron or John Miller to create a sock puppet who could about his — Trump’s — achievements. He lied to puff himself up, to generate business under false pretenses, and to play to people’s expectations…like most successful advertisers — and propagandists — he understood that the frequent repetition of easy-to-remember and simplistic taglines worked to embed merchandise and his name in potential customers’ minds.”

But Kakutani, the newly retired New York Times book reviewer, seeks to put Trump in context. Her goal is to paint the big picture: “Trump’s unhinged presidency represents some sort of climax in the warping of reality, but the burgeoning disorientation people have been feeling…traces back to the 1960s, when society began fragmenting…The assault on truth and reason that reached fever pitch in America during the first year of the Trump presidency had been incubating for years.”

She got that right. Many factors brought us to where we are today, most of them obvious only in hindsight. We’re living in the perfect storm, and Trump — its mutant byproduct, brilliantly abetted by the Russians’ exploitation of America’s fractures — is reaping the whirlwind.

I’ll leave the historical details to Kakutani. Suffice it to say that the cultural schisms of the 1960s, triggered primarily by the Vietnam war and “permissive” anti-establishment lifestyles, shattered the broad national consensus. Social and political polarization accelerated with each passing decade, and the divide was exacerbated during the 1990s by the rise of conservative media (especially Rush Limbaugh). Scholars on the left and right assaulted objectivity by preaching the gospel of postmodernism.

If you’re wondering what that is, Kakutani defines it as shedding objective reality to enshrine “the principle of subjectivity.” In other words, more and more people define their own factual truth by going with their gut and their biases.

There’s also the internet, which she writes has “led to a cascade of misinformation and relativism, as evidenced by today’s fake news epidemic” — a fertile climate for exported Russian propaganda, what the Rand Corporation, in a report, calls “a fire hose of falsehood.”

Is there any hope that America can reverse the atrophy of truth? Among the cacophony of voices in this eloquent book — everyone from John le Carre to George Washington — we get this, from fired acting attorney general Sally Yates: “Not only is there such a thing as objective truth, failing to tell the truth matters. We can’t control whether our public servants lie to us. But we can control whether we hold them accountable.”

Kakutani concurs: “There are no easy remedies, but it’s essential that citizens defy the cynicism and resignation that autocrats and power-hungry politicians depend upon to subvert resistance.”

Which is why the 2018 midterms are a crossroads for this country. All we have is our will to resist.

Dick Polman is the national political columnist at WHYY in Philadelphia and a “Writer in Residence” at the University of Pennsylvania. Email him at dickpolman7@gmail.com.