With Donald Trump in the midst of an epic temper tantrum that's likely to last until Election Day, leaving his party in tatters and his most rabid followers whipped into a frenzy of indignant rage that could easily spill over into political violence upon his inevitable defeat, it's worth taking a moment to reflect on the single most important reason why Trump must lose on Nov. 8.

From the start of his presidential campaign, Trump's opponents on the right and left have moved back and forth between two distinct (though sometimes overlapping) reasons to oppose his candidacy. First, there are the policies. Before and during the primaries, Trump's Republican adversaries took aim at his anti-immigrant stance, ran for cover when he described the Iraq War as a disaster, rolled their eyes when he ridiculed free trade agreements, and shuddered in disbelief when he proposed to ban Muslims from entering the United States. Since the general election campaign revved up, Democrats have spent considerable time doing something similar, denouncing his policy proposals as racist, sexist, xenophobic, and ignorant.

But from the beginning, there's been a second reason to oppose Trump's candidacy: his vulgar, unstable, thuggish, predatory, bullying, explicitly authoritarian character. More than ever, it's crucial to disentangle the two reasons, and to explain why the second is by far the more fundamental, indisputable reason why Trump needs to be stopped.

While many of the specific policies Trump has proposed — the Muslim ban, mass deportations, national stop-and-frisk — go well beyond what prudence would recommend or the Constitution permit, the general thrust of Trump's critique of globalism is perfectly defensible and deserves to be taken seriously.

There is nothing inherently illegitimate about opposing the centrist-internationalist consensus that has dominated politics in the Western world since the end of the Cold War. Bernie Sanders did exactly that from the left during the Democratic primaries, and at this very moment U.K. Prime Minister Theresa May is proving that a center-right politician can do something similar in a responsible and intelligent way. Certainly nothing good will come from trying to rule such opposition out of bounds on principle, since that would only drive those who dissent from the centrist liberal consensus to increasingly illiberal extremes.

If Trump possessed a tenth as much thoughtfulness and composure as May, Americans might have been edified by a lively and important national debate this year about the future direction of the country and whether it's wise to maintain or break from the reigning liberal internationalist consensus. Instead, those issues and the valid questions surrounding them have been thoroughly tainted by contact with Donald Trump's garbage heap of a soul.

None of Trump's most outrageous policy proposals or public statements — the Muslim ban, the mass deportations, the threats to journalists, the obsessive attacks on an endless series of enemies, the interest in the offensive use of nuclear weapons, the promise to jail his political opponent — follow from any coherent ideology or defined political agenda.

They flow, instead, from the lavish insecurities, grotesque self-absorption, and surrealistically exaggerated entitlement of Donald Trump the man. He craves, above all else, the furious applause and rapturous adoration of crowds — and the viciously angry, Clinton-loathing faction of the GOP that constitutes his base of support thrills, above all else, to extremism: extreme judgments, extreme threats, extreme insults.

It's a symbiotic relationship of almost perfect pathology — the needy, gluttonous demagogue and the ravenous throngs who hunger for endless shovels full of bloody red meat. Each feeds the other's deepest cravings.

Think I'm exaggerating on either side? Watch the chilling video of Trump's marathon Monday night rally in Wilkes-Barre, Pennsylvania, and behold a quasi-pornographic exercise in mutual arousal, as the would-be manipulator-in-chief and the adoring crowd continually heighten each other's righteous indignation and revel in the demonic pleasure of lashing out in increasingly deranged intensity at the world around them.

Character isn't always destiny in our political system, even at the highest levels. Some faults can be contained by the numerous institutional and procedural checks that ring the presidency. But the more comprehensive the personal defects, the greater the risk — as our nation most recently learned in the case of Richard Nixon.

But Nixon was a saint, a statesman, an archetype of steely equipoise and sober rectitude compared to Donald J. Trump. For that reason alone, the man must never be president.