Former defense secretary Jim Mattis was obviously well aware of the significance of the analogy he drew in criticizing President Trump’s lack of interest in serving as a unifying force.

“Donald Trump is the first president in my lifetime who does not try to unite the American people — does not even pretend to try,” Mattis wrote. “Instead, he tries to divide us.”

“Instructions given by the military departments to our troops before the Normandy invasion reminded soldiers that the Nazi slogan for destroying us … was ‘Divide and Conquer,’ ” Mattis later added. “Our American answer is ‘In Union There Is Strength.’

“We must summon that unity to surmount this crisis — confident that we are better than our politics,” he continued.

Comparing someone’s views, however indirectly, to those of Nazi Germany is enormously fraught, as anyone reading this understands. It’s often a rhetorical trump card, if you will, meaning it’s also overplayed — so much so that there’s an informal tenet of online conversation that any debate will inevitably terminate with a comparison to Nazism.

That Mattis nonetheless drew the comparison — from his position of authority and in this context — is remarkable.

His point is accurate. The United States is predicated both in the abstract and literally upon unity; we are not the States of America. But Mattis wasn’t simply calling upon Americans to hang together. He was reinforcing the obvious point that Trump sees no political or personal advantage in trying to do so — and so doesn’t try.

We could articulate a number of points in support of that claim: His insistence on policy proposals aimed at his political base. His immersion in culture wars elevated by his most fervent supporters. His focus on leveraging his power most explicitly on behalf of the people who voted for him. His feral disparagement of those who criticize him. His reliance on friendly news outlets for communicating with the public.

But, to that last point, we can also let Trump address the question himself. On Wednesday, even as news of Mattis's condemnation was spreading, an interview of Trump produced by the conservative outlet Newsmax was published. The interviewer? Trump's former press secretary Sean Spicer — yielding just as much rigor as when your kid interviews you about your job for their sixth-grade social studies class.

“When I was with you as press secretary, Chief Ryan Owens was killed in action,” Spicer said at one point. “I was in the Oval Office with you when you called his wife. You spoke to her in such a heartfelt way to comfort her. You provided that emotional stability that she needed at the time.”

Sometimes an interviewer leads with such a gentle introduction in hopes that the subject will be at ease, allowing the question to more easily knock them off balance. Sometimes, it’s because the interviewer is a sycophant.

Regardless, Spicer's actual question got to the point Mattis was trying to highlight.

“Do you think that right now the nation needs you to express that same sort of comfort and healing that some people need to heal right now?” Spicer asked the president.

This is the unity question, in the most frictionless possible example. Will you use your platform and the power of your office to help the country heal — in other words, to help close the fissure that exists? To unite both sides?

A normal president would begin with “of course,” and move forward from there. You can probably generate 60 words of vague consolation off the cuff that would suffice to make everyone content, if not resolve the issue.

But Trump didn’t try. He wasn’t elected to bridge the divide with Democrats; he was elected to knock down any Democrat or liberal or elite within range.

So we get this: “I think the nation needs law and order,” Trump said, “because you have a bad group of people out there, and they’re using George Floyd” — who was killed in police custody in Minneapolis when an officer knelt on his neck — “and they’re using a lot of other people to try and do some bad things. And what we do — and we have it totally under control.”

He wasn't done.

“But you have Democrat, in many cases — in all cases Democrat, super-liberal mayors,” Trump continued. He disparaged the mayor of Minneapolis (whom he later mocked for crying) and gave himself credit for ending violence and vandalism in the city. “We took that mess — it was a total mess! We brought in the National Guard. We took care of it. Now, it’s very good. If you look at that area, it’s very good.”

“So, yeah, we need healing,” he said, “but we also need strength, and we need toughness, and we need law and order. We need it all. But we do need healing.”

We need healing — but apparently you're going to have to look somewhere else for it.

That Trump was sitting down with Spicer in the first place reflects part of the problem. Trump rarely exposes himself directly to criticism, surrounding himself with acquiescent figures in his administration and largely avoiding public appearances in which he might face unsupportive people.

Trump encounters negative responses to his action most frequently (if not exclusively) through the media, through his momentary dalliances with CNN and MSNBC and in objective coverage he sees in The Washington Post and other newspapers. He doesn’t modify his position or appeal to his political opponents in part because he faces no pressure to do so. He doesn’t engage with those he disagrees with because he either ignores them or simply categorizes them as enemies. That he’s president without ever having to engage seriously with Democrats taught Trump that he could serve that way, too — and he has.

At the end of the interview with Spicer, his former employee asked the president if there were hires he’d made that he regretted (besides former attorney general Jeff B. Sessions). Trump didn’t mention Mattis because he hadn’t yet seen Mattis’s comments about him. When he did see Mattis’s comments, he threw out a few tweets of the predictable sort.

Trump did not contest Mattis’s criticism of his failure to unify the country. How could he?