That order was almost certainly not the product of intelligence analysis about the threat posed by immigrants from certain nations, but rather the president trying to fulfill a campaign promise based on exaggerated fears about immigrants and unfair criticism of the refugee vetting system. One former senior intelligence official told me that when the ban was announced internally, everyone was simply told to get on board.

I joined several other former directors and acting directors of the C.I.A., two former deputy directors, a former director of national intelligence and a former head of the National Counterterrorism Center and others in filing an amicus brief opposing the ban. The people now occupying our old positions were notably silent on the merits of the order.

Over time it has become clear to me that security decisions in the Trump administration follow a certain pattern. Discussion seems to start with a presidential statement or tweet. Then follows a large-scale effort to inform the president, to impress upon him the complexity of an issue, to review the relevant history, to surface more factors bearing on the problem, to raise second- and third-order consequences and to explore subsequent moves.

It’s not easy. The president by all accounts is not a patient man. According to The Washington Post, one Trump confidant called him “the two-minute man” with “patience for a half page.” He insists on five-page or shorter intelligence briefs, rather than the 60 pages we typically gave previous presidents. There is something inherently disturbing in that. There are some problems that cannot be simplified.

Sometimes, almost magically, he gets it right. The president’s speech last August on Afghanistan was worth listening to, clearly the product of the traditional deliberative process where intelligence sets the picture based on the best available information, and then security agencies weigh in with views that are adjudicated by the National Security Council.

But the Afghan experience has been the exception. The president continues to attack the Iranian nuclear deal and is likely to end it even in the face of intelligence that Iran has not committed a material breach of the compact, that the deal makes it more difficult for Iran to build a weapon and that it gives us visibility into its nuclear program.

Then there is Russia. The president only recently and grudgingly agreed to impose sanctions on Russians believed to have interfered in the American election, and he continues to characterize the investigation as a “witch hunt” while relentlessly attacking agencies of his own administration.