What would Greenstein make of President Trump?

That Donald Trump is a uniquely unpredictable president is no longer a controversial observation. When POTUS is threatening to jail political opponents, announcing policy on Twitter in the early hours of the morning, or convening campaign rallies after less than six weeks in office, you know you’re in uncharted territory. But what does Trump’s irascibility say about his ability to actually do the job?

Fred Greenstein, the Princeton professor and scholar of American presidents, would probably know better than most. And in an article accompanying his seminal book The Presidential Difference, published in 2001, he delivered a stern warning. “Beware the contender who lacks emotional intelligence. In its absence, all else may turn to ashes.”

It’s clear that whatever Americans think of his policies, a majority of them don’t believe Trump has the “proper temperament” for the Oval Office (both liberal and conservative pollsters agree). Yet Greenstein asserted that this quality, above all others, could make or break an administration. Even intellect and vision, in his view, were less important. For politicians who exhibit “mood swings,” “rigidity,” “anger and suspicion,” he said, could find their political skills fatally undermined.

Back in 2008, as an undergraduate, I wrote a paper which searched for Greenstein’s five essential presidential qualities among the candidates in that year’s primaries. What happened next was evidence of the truth in Greenstein’s warning: John McCain was dogged by criticism of his temperament; Hillary Clinton was at turns accused of being both cold and insincere. Barack Obama’s signature, however divisive his presidency seems now to have been, was emotional intelligence: the ability to read a room, pick just the right tone for the occasion, and keep his cool. He was swept into the White House largely off the back of that personal quality.

Two things about emotional intelligence. First, it is non-partisan. Everybody notices it, whatever else they think of you. If he can’t empathise with people, Trump will eventually lose goodwill even with some of the most hardened conservatives. Second, it is not obsolete in 2017. Its importance to human relationships, to our whole lives, is permanent, and hasn’t been eroded by the digital age (in fact, some people argue that it’s more important than ever).

Greenstein is 86 now; I don’t think he’s written anything about President Trump. I’m sure he’s as fascinated as the rest of us. In another prescient moment, he observed that an increased ability to “command public attention and shape the national policy agenda” could make even a flawed politician more potent (remember, Twitter didn’t exist yet). But Greenstein’s golden rule, while it didn’t predict Trump’s rise, may yet give us a clue as to his fall.