Andrew Harnik / AP

Against all odds, something insightful finally came out of Donald Trump’s mouth.

When Trump closed the second presidential debate by praising Hillary Clinton as a fighter, he spoke volumes about why she should be the next president. Not only did the comment spotlight a key reason to vote for Clinton, who has spent her entire adult life battling for such worthy causes as better treatment for migrant workers and disadvantaged children, but Trump again proved to be a disaster when working without a script.

This time, the damage he inflicted was to his own campaign. After repeatedly contending that Clinton didn’t have the stamina to be president, he then dropped a cluster bomb on his own argument by lauding her tenacity and saying she “doesn’t give up.”

Surely, his handlers were wincing — at least those who hadn’t passed out. But that’s Trump, who was as scattered and erratic as ever.

Miracle of miracles, though, he happened to be dead right about Clinton.

Her record of public service and top-level government experience in the face of withering personal and political attacks make her the obvious choice for the presidency.

She’s a tested, unshakable leader who has built a powerhouse resume for the White House: social-crusading lawyer, first lady, senator and secretary of state. At each point in her career, she displayed boldness and courage — fighting for women’s equality and affordable health care, proving effective in working with her colleagues in the Senate, and shaping economic sanctions against Iran that forced it to the negotiating table on nuclear arms development, to name a few accomplishments.

Clinton hasn’t been perfect. For instance, she admitted she made a mistake by using a private email server as secretary of state, and she has a tendency to be her own worst enemy with the media by becoming defensive, dismissive and nontransparent when pressed.

But perfection isn’t a requirement for the Oval Office. And among the characteristics that are prerequisites — experience, temperament, judgment and capability — Clinton is the hands-down choice.

Trump, as he has now proved beyond a shadow of a doubt in debates and campaign events, is unprepared, unfit and unhinged.

There’s not enough room in this magazine to detail all of the reasons he shouldn’t be elected. Items high on the list would include his praise of Russian strongman Vladimir Putin, his call for proliferation of nuclear weapons, his refusal to release his tax records, his alarming lack of details about his plans on such issues as the economy and health care, and his compulsion to insult people.

He’s demeaned, belittled and offended the disabled, Muslims, women and Mexican immigrants, among other groups. When he offered a rare apology after his “Access Hollywood” remarks from 2005 were revealed, it was tepid. He said he was sorry if anyone was offended by his “locker room talk,” bragging about sexually assaulting women.

In any other year, any one of Trump’s disgusting displays would have been enough to derail him.

But this year, he’s become a monster empowered by anger and fear and bolstered by decades of the Republican Party’s political and media machine vilifying public servants and casting the government as an enemy of the people.

So we’ve reached the sad depth at which some Americans champion Trump as a political outsider, regardless of how repulsively and egotistically he behaves. That group shrank in the aftermath of the “Access Hollywood” scandal, which was reassuring, but there still are supporters who refuse to see Trump for the hate-mongering, unethical and immoral threat he is.

That’s heartbreaking, but the encouraging part about this forced march of an election is that Clinton offers voters a chance to choose a president who’s fully prepared to take over the job — and who, for decades, has proved that she’s in it to serve the public.

The Sunday enthusiastically endorses her.