We already knew that Donald Trump's new ban against transgendered troops in our nation's military came as a surprise to military leaders. Now we're learning that the impetus for the sudden policy change was considerably more crude than even detractors suspected.

The short version? Politico reports that Donald Trump announced a ban on transgendered military members because he was frustrated with the government's lawyers trying to explain the implications of such policies to him.

President Donald Trump’s White House and Defense Department lawyers had warned him against the transgender military ban for days. They were concerned about the ramifications of the policy, how military officials would respond and what legal backlash it could cause, two West Wing officials familiar with last month’s discussions said. The lawyers thought there would be plenty of time for more discussions and were analyzing arguments. Frustrated with being “slow-walked,” in the words of one White House official, the president took to Twitter last week — jarring many in the West Wing out of complacency and startling his lawyers, Defense Department officials and West Wing aides, who learned of the change in a series of tweets.

This is remarkable reporting, and paints a picture of Trump as exactly the sort of unstable, petty know-nothing that his worst critics feared. His advisers had come to him with a new policy request—originally, it seems to have been the Republican lawmakers' demands to bar the military from paying for gender transition and hormone therapies. The implications of this were being hashed out by administration and military lawyers at the time; at some point, in the White House, this evolved into a discussion of banning transgendered service members outright. Possibly, and this is speculation on our part, because it would require fewer words.

Apparently, however, it was these discussions themselves that set Trump off. Too dim or hotheaded to grasp the nuances of the issue and too impatient to tolerate substantive explanations of it with others, he instead lashed out with his new, most simplistic "policy" banning transgendered service members apparently as an attempt to stop his own staff from asking him further questions on it.