“There’s just something about this job as President . . .” George W. Bush observed last week, in an interview with NPR. “You think one thing going in and then the pressures of the job or the realities of the world, you know, are different than you thought.” Bush wasn’t reminiscing about his own Presidency; he was “opining,” he said, about the current one. The reality that Bush had in mind—the one that he hopes President Trump will embrace—is that it is in America’s national interest “to be allies with Mexico and not alienate Mexico.”

Trump, of course, has invested a great deal of energy in denying that particular reality—along with many others, from the existence of climate change to the role of Russian meddling in last year’s Presidential election. Yet, in recent weeks, Trump has conceded that he might, in fact, have been wrong about a thing or two, and now stands corrected. “It turns out” and “nobody knew” are two of the signal phrases by which Trump indicates that an epiphany has arrived: that health-care policy is “so complicated,” or that North Korea is not a Chinese client state. “After listening [to President Xi Jinping, of China] for ten minutes, I realized it’s not so easy,” Trump told the Wall Street Journal earlier this month. Never mind the obviousness of these statements, or Trump’s weird guilelessness in presenting them as insights; they are being received, by some, as signs that Trump is growing in office. “I think President Trump is learning the job,” Mitch McConnell, the Senate Majority Leader, said last week.

Learning the job, in fairness, is a big task for any new President. “Regardless of his prior training, nothing he has done will have prepared him for all the facets of that job,” Richard Neustadt, the great scholar of the American Presidency, wrote in “Presidential Power,” his influential study, in 1960. All Presidents, he argued, enter office ignorant, innocent, and arrogant—liabilities it can take two, three, or even six years for them to overcome. Some never do. Neustadt saw “a certain rhythm” in the Presidential learning process, and, indeed, in most cases, it follows a well-worn path: the chaotic cram session of the transition; the headiness and disappointments of the first year; the midterm elections in the second (a “shellacking” of the President’s party, as Barack Obama described it in 2010, tends to dispel any lingering arrogance); and, of course, the crises—domestic and foreign—that come without warning. The education of a President is episodic, driven by events. The results, as we know, are uneven. They depend not only on fate but on the answers to three basic questions: what are the “particulars of [a President’s] ignorance,” in Neustadt’s phrase; does he have the humility to acknowledge them; and does he have the capacity—political, moral, intellectual—to address them? ...