I recommend that you take the considerable time it will take to read Patrick Radden Keefe’s piece in The New Yorker on H.R. McMaster. Of course, McMaster was recently fired as President Trump’s National Security Adviser. The move was rumored for months, but it seems to have had a very specific cause.

On March 20th, Trump had a scheduled call with Vladimir Putin. As is the custom when a president calls another head of state, the National Security Council prepared notes and talking points for the president. These notes were not as detailed as they had been for prior presidents.

The National Security Council has a comparatively lean budget—approximately twelve million dollars—and so its staff consists largely of career professionals on loan from the State Department, the Pentagon, and other agencies. When Trump assumed office, N.S.C. staffers initially generated memos for him that resembled those produced for his predecessors: multi-page explications of policy and strategy. But “an edict came down,” a former staffer told me: “ ‘Thin it out.’ ” The staff dutifully trimmed the memos to a single page. “But then word comes back: ‘This is still too much.’ ” A senior Trump aide explained to the staffers that the President is “a visual person,” and asked them to express points “pictorially.”

It’s true that people learn in different ways, and if Trump retains information better when it is presented pictorially, then his materials should certainly employ liberal use of charts, photographs and the like. It seems like the problem may be more related to his attention span and impatience with complexity, however, than how his brain processes information.

“By the time I left, we had these cards,” the former staffer said. They are long and narrow, made of heavy stock, and emblazoned with the words “the white house” at the top. Trump receives a thick briefing book every night, but nobody harbors the illusion that he reads it. Current and former officials told me that filling out a card is the best way to raise an issue with him in writing. Everything that needs to be conveyed to the President must be boiled down, the former staffer said, to “two or three points, with the syntactical complexity of ‘See Jane run.’”

For this reason, the National Security Council staff prepared a long, narrow, heavy-stock card that had the words “DO NOT CONGRATULATE” printed on it in capital letters. Vladimir Putin had just won another term as president of Russia in what was essentially a sham-election involving demonstrable fraud. Giving him credit for it would send the wrong message on a host of fronts. Even from a strictly political point of view, congratulating Putin would be a bad look for Trump.

H.R. McMaster was surely aware that the card would be in Trump’s slim deck, and he must have hoped against hope that it would be enough to dissuade from offering his congratulations because he didn’t bring the subject up himself.

Trump also received a five-minute oral briefing from his national-security adviser, Lieutenant General Herbert Raymond McMaster, who goes by H.R. Before McMaster delivered the briefing, one of his aides said to him, “The President is going to congratulate him no matter what you say.”

“I know,” McMaster replied.

When Trump made the call, the first thing he did was congratulate Putin on his electoral success. Obviously, the National Security Council staff was completely exasperated. It quickly leaked that they had tried to prevent this from happening. The whole world learned about the long, narrow, heavy-stock card that had the words “DO NOT CONGRATULATE” printed on it in capital letters.

Trump was embarrassed and infuriated, and he fired McMaster two days later.

There’s one more part of Patrick Radden Keefe’s piece that I want to share with you. It’s on the subject of how the National Security Strategy paper was crafted last year under McMaster’s guidance. There are a variety of things you can take away from this excerpt, none of them good in my estimation.

In December, the White House unveiled its “National Security Strategy,” a sixty-eight-page document in which the N.S.C. staff laid out Trump’s official view of the world. McMaster’s aides proudly claimed that this was the first time a national-security-strategy document had been published within the first year of a Presidential Administration. The document had conspicuously Trumpian lacunae; there were no references to climate change as a national-security threat, for example. But it seemed to be an effort to domesticate some of Trump’s bellicose rhetoric, emphasizing the importance of competition among the great powers but also of American leadership. Trump had mocked NATO as “obsolete”; the document described the alliance as “one of our greatest advantages.” It explicitly named Russia and China as malign influences, and declared that the Russians had used technology “to undermine the legitimacy of democracies.” Such language was in sharp contrast with Trump’s strenuous avoidance of blaming the Kremlin for election interference. An N.S.C. official told me, “The fundamental question is, can you divorce Presidential rhetoric from American foreign policy?”

Composing the document was a challenge, because Trump did not have many concrete views on foreign policy beyond bumper-sticker sentiments like “America first.” When McMaster requested Trump’s input, the President grew frustrated and defensive, as if he’d been ambushed with a pop quiz. So staffers adopted Trump’s broad ideal of American competitiveness and tried to extrapolate which policies he might favor in specific instances. McMaster touted the resulting document as “highly readable,” and as a text it seems reassuringly plausible. But nobody on McMaster’s staff could confirm for me with any conviction that the President himself had read it.

What sticks with me is the image of McMaster coming to the president to get his input on what should be in the nation’s statement of national security policy and discovering that he’s just making Trump feel stupid and defensive and inadequate, like he’s been given a pop quiz for which he hasn’t prepared.

It’s related to Trump’s anger at being provided reading materials, like it’s unwanted homework or asking a fourth grader to do trigonometry before he’s allowed to play with his Xbox.

It’s not just that Trump cannot perform the duties of commander in chief. He doesn’t want to even make an effort to fulfill those duties. When confronted with them, he is apparently is overcome with feelings of inadequacy that make him lash out or shut down.

And it’s not just that he can’t consume or process a bare minimum of the information he needs to make decisions, but that he doesn’t listen to the little information that does make its way into his brain. This is also obviously the case with his lawyers, but that’s largely a problem confined to Trump and his future prospects of remaining president and out of prison. When his shortcomings involve our national security, it’s a problem for all of us and the people of every nation.

In the end, Trump’s removal from office could be justified on the same kinds of grounds that forced Spiro Agnew out, which was basically corruption that preceded his run for federal office. Or it could be justified on the grounds that forced Nixon out, which was basically a break-in of the Democratic National Headquarters followed by a massive coverup. But it’s his inability to do the job of commander in chief that is really the primary reason he should be removed from office, and the reason his own cabinet should invoke the 25th Amendment.