Many of us cast last week’s Republican debate in Cleveland as entertainment—I have heard the thought repeated many times—but this seems to me a cheap dodge. To laugh at the assembly of 10 right-wing presidential aspirants for two hours of questioning is to flinch from a truth too heavy to bear even as we must. The Fox News spectacle counts as entertainment only as tragedy does.

Given the position these people seek, the decisions the next president will make, how seriously our media and many voters take them, and the money lining up to advance one or another of them into office, we have just been advised of how very perilous the American predicament is at this moment. Bad as the candidates’ domestic agendas are, the danger is greater, far greater, on the foreign policy side, and this is our topic.

Somebody smart recently defined tragedy as the difference between what is and what could have been. This is the thought: We have a brief time left to correct our course before the American experiment begins to self-destruct beyond retrieval, and we have not yet proven strong or brave or honest enough to make the move. To me, this is what makes last Thursday’s spectacle tragic rather than comic.

I have thought since the Tea Party’s appearance on the political scene half a dozen years ago that the American right was destined to destroy itself before our eyes. Last week’s G.O.P. display—it was politics as spectacle, not a debate—convinces me of this. The Republican Party as it has been in history is already gone, more or less, and is being replaced—more swiftly than one would have thought possible—with what amounts to a fanatical fringe.

Good enough that the Republicans tip into unreason, you might think. But who could have guessed that irrationality was a winning political platform? Who would have imagined even a few years ago that the Rockefeller wing of the party was so spineless and desperate to win Washington that it would capitulate to extremists thoroughly incompetent to address the 21st century’s self-evident realities?

The question to come is whether the American electorate will commission those who have usurped the G.O.P. to destroy a lot more than the party. Put any one of these people in office and Americans will forfeit their chance to participate constructively in a self-evidently emergent world order, to escape a past that now haunts us, to act abroad out of something other than fear.

We have to start with Donald Trump to understand what we are getting from the right flank of our right-wing nation. It may seem unlikely, but Trump and the reaction to him among his G.O.P. opponents took me right back to my years as a correspondent in Tokyo: Every so often a cabinet minister in the long-governing Liberal Democratic Party would make some egregiously unsound remark about the righteousness of Japan’s Pacific war, objectionable Westerners or the inferiority of the Chinese. The next day he would be sanctimoniously removed from office and forced to provide a ritualized apology that meant nothing.

What was the offending minister’s sin? It lay not in his thinking or convictions, one came quickly to recognize, but in articulating publicly the views of all orthodox Liberal Democrats.

This is Trump among his fellow Republicans. Post-Cleveland, I think of him as the id of the G.O.P. The other 16 candidates detest him more than any Democrat does, I would wager, because there is no air whatsoever between the Donald’s views—assuming they remain stable long enough to make them out—and those of anyone else vying for office in the reconstituted G.O.P.

All that marks out Trump from other Republican aspirants is his presentation, the too-blunt-to-bear crudity of his prejudices against too many things and people to count, his hollowed-out presumptions of American primacy, his impossible promise to lunge backward to “make America great again.”

In a word, Trump comes up with the wrong affect. And there is no understanding the spectacle American politics has become, or why this nation conducts itself so recklessly abroad, unless we grasp the importance of affect in the American consciousness and American public life.

Trump is correct in his estimation of what a right-wing American pol has to be to get anywhere: dismissive of the Other, intolerant of all alternative perspectives, suspicious of thought, given to action (preferably violent) while indifferent to its consequences. Trump’s ultimate sin—a paradox here—is to possess an affect so plainly the sum total of what he has to offer that it exposes the rest of the Republican crowd: They are all empty but for slightly varied poses. All they have for us is affect.

* * *

Since the days of Jefferson, Americans have cast themselves as “a people of feeling,” to borrow a phrase from the historian Andrew Burstein. Ours was a “culture of sensibility.” Americans, in other words, tended to rely on feeling, as opposed to thought, to understand a given question or fix a given problem.

This New World trope was part of what made Americans American. Yes, America was the flower of the Enlightenment and authority derived from law. But reason was not the source of true conviction in American culture. Emotional experience was, as the Great Awakening of the 1730s made starkly plain. One felt, one was converted, then one believed.

The sentimental aspect of the American character assigned great importance to affect. Bearing, demeanor, attitude, posture—these things took on a certain patriotic dimension. A good American had to be observably American.

To be “affectionate,” indeed, was part of what it meant to be American in the early years. But the peaceable, generous, good-willed Americans of the 18th century gave way in the 1820s to the Jacksonian kind of American: Aggressive, uncompromising, masculine in the traditional manner, suspicious of intellect and sympathy, given to swift action and simple justice.

You can see where this leads easily enough.

Think of all the Hollywood films and television programs you have wasted your time watching. Think of John Wayne, Joe Friday, Hoss Cartwright and everything Clint Eastwood has ever done. Think of “Duck Dynasty.” To a very weird extent, our culture consists of a never-ending lesson in the proper American affect. Now as in the 18th century, it is affect that distinguishes us and proves us patriotic.

Same thing in our national political life.

Al Gore was a lousy candidate because his demeanor was wooden—“hard to like the guy.” Bill Clinton can say “I feel your pain” and thus we find faith in his policies. Bush II reports of Putin, “I saw into his soul,” and it is honored as serious comment. Sarah Palin attacks Obama for speaking well, which means he is not “a real patriot.”

And here we are in 2015. Scott Walker says of the most significant diplomatic accord to be negotiated in decades, “We don’t need more information… we need decisive leadership and we need it now…. The United States needs a foreign policy that puts steel in the face of our enemies.”

It says nothing and everything, doesn’t it? Nobody in Cleveland last week said anything of substance, either. Jeb Bush gave one of his foreign policy speeches Tuesday, and again, while he said nothing, the presentation told the whole story. The right wing in American politics is still quoting the 18th century: What matters most is the affect of the man or woman who holds our highest office.

As may be plain, I assign the 2016 presidential contest a large psychological dimension. The policy positions will count, of course, and I will get to them, but what is most fundamentally at issue is the character of the American consciousness.

To strip the point to the simplest terms, we are in an argument between affect and thought, or between feeling and reason. We need to have it, but right-thinking people must recognize that we do not have much time to get it done.

To substitute affect for thought, as all G.O.P. candidates propose, is dangerous for two reasons. First and very practically, it almost inevitably produces bad results. Bush II’s invasions of Afghanistan and Iraq in the post-September 11 period are obvious but not isolated cases. The need was to look tough, to act without thinking, to declare “mission accomplished” on an aircraft carrier’s deck.

Second, affect is a dangerous appeal to the subconscious in us. It addresses unsayable fears, resentments and insecurities, and fortifies idealized selves, self-images derived from impossible Hollywood plots and characters. In this respect it is the doorway to irrational politics and behavior, especially in our conduct abroad.

To complete the thought, while affect may be mistaken for charisma, the two are very different. The latter is a many-sided attribute in a man or woman. Charisma draws its power from thought, insight, imagination, wisdom; it leads people to new understandings, ways of seeing they never knew were possible.

Affect is by comparison one-dimensional. It reduces politics to spectacle, so it is ersatz, WalMart charisma at best. Reagan, who dragged America back into the politics of affect after the defeat in Vietnam, was the master—and hence the idol of all 10 men on the stage in Cleveland. Bobby Kennedy (the later Bobby) or Mandela were by contrast charismatic figures.

Two exceptional pieces on the Republicans have come out since Cleveland. Both shed good light on what the Republicans propose to offer voters as they try to win back the White House.

Last Friday Paul Krugman, the Princeton economist and New York Times columnist, published an opinion item headlined, “They Can’t Be Serious.”

“While it’s true that Mr. Trump is, fundamentally, an absurd figure, so are his rivals,” Krugman writes. “Talking nonsense is what you have to do to get anywhere in today’s Republican Party…. Or to put it another way, modern Republican politicians can’t be serious—not if they want to win primaries and have any future within the party. Crank economics, crank science, crank foreign policy are all necessary parts of a candidate’s resume.”

There is something in this not to be missed. In effect, the Republicans’ gamble is that the denial of the realities with which we live will prove attractive to enough voters to put a G.O.P. candidate in the White House. Two big things are at stake here. One, the Republicans may turn out to be right. Two, denial is essential to the right wing’s position. They are committed to refusing any acknowledgement of the requirements the 21st century imposes upon us.

Denial is totemic, then—a kind of ritual of refusal. It reflects, and I would say unmistakably, a deep, subconscious fear abroad among us. Many voters want to see and hear denials. They depend on the irrationality of each one.

This is what I mean by a self-destructing party—and the danger all of us will face if we get a Republican victory next year. We will be made prisoners of our past in all its real and imagined aspects. It is not possible, of course, to live well in such a space.

A few days ago the Atlantic published Peter Beinart’s “The Surge Fallacy,” an essay on the return to Bush II foreign policy postures. We have had next to nothing other than bluster from Republican aspirants so far, but again, these people say nothing but tell us everything. Beinart describes a kind of subterranean drift in the right-wing orthodoxy—yet another attempt to lunge backward into permanent avoidance.

“Over the past decade, the foreign-policy debate in Washington has turned upside down,” Beinart begins. “As George W. Bush’s administration drew to an end, the brand of ambitious, expensive, Manichaean, militaristic foreign policy commonly dubbed ‘neoconservative’ seemed on the verge of collapse…. That was then. Today, hawkishness is the hottest thing on the American right. With the exception of Rand Paul, the G.O.P. presidential contenders are vying to take the most aggressive stance against Iran and the Islamic State, or ISIS. The most celebrated freshman Republican senator is Tom Cotton, who gained fame with a letter to Iran’s leaders warning that the United States might not abide by a nuclear deal…”

Beinart identifies a new rewrite of the Iraq narrative—wherein Bush won the war with his 2007 “surge,” and the Obama administration punted it by withdrawing American forces—as the signal moment in this latest iteration of American militarism. The “surge fallacy,” as Beinart calls it, was Jeb Bush’s theme, made ad hominem with an attack on Hillary Clinton, when he spoke Tuesday at—where else?—the Reagan Library in Southern California.

What are we to say when the Republican candidate who trades on an image of moderation—this is his affect, of course—turns out to be as ungiven to reason as the worst in the lineup? The follow-on problem here is that, however well or badly the Republican candidate does in the election, he or she can force any Democrat, with the possible exception of Bernie Sanders, to cast America’s foreign policy alternatives in proximately unreal terms.

The American right’s new hawkishness, thus, is not a sickness from which the rest of us can claim immunity. There is none for Americans. In a remarkable appearance at the Reuters newsroom in New York Tuesday, Secretary of State Kerry put the point as forcefully as he has ever said anything: “Our allies are going to look at us and laugh,” he warned, if this country’s rightists kill the accord with Iran.

Then this: “It’s not going to happen overnight. But I’m telling you, there’s a huge antipathy [to U.S. leadership] out there. There’s a big bloc out there, folks, that isn’t just sitting around waiting for the United States to tell them what to do.”

Last week’s message from Cleveland is simple and stark, it seems to me. The politics of affect must be understood for what it is and then decisively countered if we are to advance into that place known as the 21st century.

This means we have to stop pretending to take posing politicians, those who dress up fear as courage, as credible voices in the conversation Americans need to have. Let the media write about them as if they are serious. They are serious only as measures of how much needs to get swept away.

These judgments may seem Cassandra-like, but so be it. It seems to me Cleveland also told us that the political season to come could prove a last, best hope for who knows how long to alter the course to destruction we remain on.