The furor arising out of Donald Trump’s blatant disrespect for Khizr and Ghazala Khan, the Muslim couple whose son, Captain Humayan Khan, was killed in action in Iraq twelve years ago, demonstrates just how frightening this election cycle has become. The scariest part is not that Trump takes pride in his own political incorrectness, or that he thinks he is infallible, or even that he defies the standards of basic human decency. He does all of those things, which in combination make him uniquely unfit to hold the office of President.

None of those is the heart of the problem, however, because the heart of the problem is not Donald Trump. Sure, Trump raises narcissism to an art form, but so what? Egotism is an occupational hazard of politics. Trump is an extreme case, but if you put enough egotistical politicians together, it is likely that sooner or later, at least one of them will, as Trump has done, demonstrate narcissism at a level that is truly pathological. Yet remarkably, with the possible exception of Richard Nixon (and I’m not convinced it’s true even of him), no American President — and until Trump no major party nominee for the Presidency — has been so pathologically narcissistic that he would constitute a clear and present danger to the Republic.

In part, that’s because we’ve been lucky, but it’s also because those who created our constitutional system were wise. They understood that human nature would inevitably produce a hunger for power, so they carefully created a system of checks and balances designed to prevent any one center of power from overwhelming the others. Even if you hold up Nixon as a counterexample, the results of Watergate made it clear that our constitutional system was strong enough to withstand misconduct even at the pinnacle of power.

The advent of nuclear weapons, however, poses a particular challenge to the constitutional balance of power. At the risk of belaboring the obvious, modern technology has created weapons so destructive as to threaten the existence of humanity. A decision to deploy such weapons in a crisis would need to be made within minutes, far too quickly for our system of constitutional checks and balances to be useful.

Until such time as we can devise some other way of preventing modern technology from inadvertently destroying human civilization, we will need to create a fail-safe that is one step removed — preventing anyone so unstable that he or she cannot be trusted with that awesome power from attaining that office. That may require some patriotic politicians to do the almost unthinkable, placing country above party. It’s worth remembering that Watergate — the closest we’ve come to a nuclear age constitutional crisis — was ultimately resolved when the Republican leadership in Congress made it clear that they would not back the continuation in office of a President of their own party.

The heart of the Trump problem is not simply his narcissism, but the lengths to which decent, seemingly rational Republicans and Republican sympathizers will go to avoid anything that might help Hillary Clinton become President of the United States. As the campaign continues and Trump moves from one outrageous statement to another, the majority of Republicans are apparently still willing to allow Donald Trump to become President as long as they can avoid leaving their fingerprints on his Oval Office key.

Trump’s treatment of Captain Khan’s parents is a particularly egregious example because even his supporters haven’t really tried to defend him. One of the unwritten rules of political etiquette in this country — one that we might expect even Donald Trump to understand — is that you respect the grief of parents whose children have been killed while serving their country in uniform. Trump violated this unwritten rule, but even that was by no means the worst of it. He also: (1) further insulted Capt. Khan’s faith by claiming that his mother’s failure to speak at the convention showed Islam’s attitude toward women; (2) equated his own “sacrifice” by running successful businesses with Capt. Khan’s ultimate sacrifice; and (3) claimed that the Khans “viciously” attacked him by questioning whether he had read the Constitution — though he stopped short of saying they were wrong.

The Khan controversy has finally gotten us to the point at which a significant number of Republicans (though still a minority) have begun to abandon their standard bearer. The majority so far would seem to prefer pretending that Trump can become (as he has put it) “presidential” rather than admit the obvious: that the Republican primary electorate has anointed a nominee so utterly unfit for high office as to represent a danger to the country if not the world.

It’s finally beginning to look as if some Republicans are getting the message. In what may be the supreme irony, it has taken the dignified grief of the Muslim parents of a soldier killed in action to bring the country to its senses. We cannot afford to be complacent, but we may survive this crisis, albeit with no margin to spare.

How did we get to this point? There will be time enough when the immediate crisis has passed to ponder that question. It seems to me, however, that at least part of the answer lies with the tone of our politics. When you proclaim, loudly and frequently enough, that your adversary is the Devil himself (or herself), sooner or later you may come to believe it. If you adamantly insist that your adversary’s election would constitute a clear and present danger to the country, there’s a serious risk that you won’t be able to recognize a real danger when it comes along. Even if you realize that your rhetoric is campaign hyperbole, moreover, some of your followers may not be as careful in making that distinction.

God created the world with words, the Torah teaches us, and while our words are less powerful than His, they are often more powerful than we realize. Armed with words, human beings can do great good and great evil. But when we overuse words, or use them carelessly, they can lose much of their power. As we contemplate what I hope will be a decisive aversion of the catastrophe of a Trump presidency, we must demand that our politicians and opinion makers become somewhat more restrained In their rhetoric.

We can all begin by turning down the volume.