At several moments during the third presidential debate, and especially in its first half hour, the country caught a fleeting glimpse of what might have happened this year if the Republican Party had nominated a half-way competent candidate to compete against Democrat Hillary Clinton.

On the Supreme Court, Clinton said, in effect, that she thinks the Court should serve as a second legislative body in which liberals hold a majority of the seats and exercise veto power over the other branches of government.

On abortion, her position was so extreme that she managed to make Donald Trump sound, for perhaps the first time in his entire life, like a paragon of level-headed reasonableness and moral decency.

On her statement (contained in leaked transcripts of her speeches to financial institutions) about dreaming of a hemisphere-wide free trade zone with open borders, she sounded shifty and defensive.

On her handling of her private email server as secretary of state, she simply tried to change the subject.

On her record of foreign policy judgment calls, especially with regard to Iraq and the greater Middle East, she dodged and weaved, no doubt because her record is extremely spotty.

In sum, Hillary Clinton was who she is and who senior members of her inner circle admit privately that she is: a weak and highly vulnerable presidential candidate who would have had difficulties competing against almost any opponent.

But of course Donald Trump isn't any opponent. He's a catastrophically flawed opponent — a man consumed by anger, resentment, and contempt; who lies and exaggerates flagrantly, transparently, and continuously; who treats women like garbage and then flamboyantly pronounces that "no one respects women more than I do"; who tosses off gratuitous insults for no discernable reason at all ("such a nasty woman"); who thinks nothing about throwing around civically poisonous nonsense about "rigged" elections and then refuses to back away from the accusation even when given the chance; who manages to demonstrate dozens of times in 90 minutes on a debate stage that he has no business getting within half a mile of the Oval Office.

So even when Clinton's flaws were exposed — by a question posed by moderator Chris Wallace, by Clinton's own imprecise statements, or by Trump's relentless barrage of hostile accusations — Trump was always there to blunt the impact and distract attention from it.

This happened over and over again, especially in the second half of the debate, as Trump became increasingly agitated and harshly aggressive.

Clinton gets asked to defend her record and Trump's right there to make the ludicrous charge that the State Department "lost" $6 billion during her time at the helm.

Trump raises questions about various WikiLeaks revelations with regard to the Clinton campaign, which Clinton turns into an attack on Russia's meddling in the election — and Trump decides to respond by … rising in partial defense of Vladimir Putin. (This allowed Clinton to accuse Trump of being Putin's "puppet.")

And on it went, through Trump's taxes, his revolting comments about and alleged behavior toward women, his reckless statements about foreign policy and immigrants. Every time it looked like Clinton might be on the ropes, she managed to pivot to some outrageous or insulting or irresponsible comment that Trump has made over the past 16 months.

Trump's replies? They rarely amounted to more than petulant and peevish gesturing in the direction of a rebuttal. If you're inclined to trust Trump (someone must, right?) and you spend all day immersed in Fox News and Breitbart, then maybe some of Trump's responses to Clinton in the debate's final 45 minutes made semi-coherent sense. But I suspect most viewers were left thinking, "What the hell is this guy ranting about? He sounds like a lunatic."

And there you have it: Hillary Clinton won the third debate, like she will win the election itself, for the simple and compelling reason that she isn't a lunatic.