Call it the “electric fence presidency.”

President Trump — always confident, always exuberant, always selling — crashes forward with the policies and people he embraces until he hits a shocking obstacle and falls back, at first stunned and disbelieving, but resolving quickly not to get scorched that way again. He adjusts his trajectory and takes off again, pursuing the same goals on an altered path.

In an interview with Attorney General Jeff Sessions this month, I was incredulous at Sessions’s insistence that there was no choice he could make that wouldn’t lead to family separation at the border. It was obviously a morally objectionable practice and just as obviously political suicide. The gathering storm of a public-opinion backlash broke quickly thereafter and increased in severity as journalists descended on the border and parents and grandparents across the country shuddered at the images of children separated from parents charged with misdemeanors.