Watching news coverage in the ensuing days, Trump was affected by images of impassioned high school students, many of them tearfully calling on federal lawmakers to take action, according to one White House aide. Yet even in times of tragedy, Trump has always been a base-conscious politician — somebody who looks to shore up his most fervent supporters rather than to reach bipartisan compromise.

One White House source told POLITICO that he and fellow administration officials were taken aback by the bump stock announcement. They’d received no heads up, the person said, and wondered privately whether Trump simply wanted to blunt accusations that he wasn’t acting decisively.