Trump's biggest weakness | CNN

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Fareed's Take: Trump is a BS artist

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Julian Zelizer: Donald Trump hasn't demonstrated the set of skills needed to handle the powers and constraints of the presidency

Temperament is a hugely important requirement for the White House, Zelizer says

Editor’s Note: Julian Zelizer is a professor of history and public affairs at Princeton University and a New America fellow. He is the author of “Jimmy Carter” and “The Fierce Urgency of Now: Lyndon Johnson, Congress, and the Battle for the Great Society.” The opinions expressed in this commentary are his.

(CNN) —

Donald Trump has a temperament problem.

The anger that he has consistently displayed in public and his tendency to lash out against his critics, whomever they might be, even the parents of a slain soldier, has sent Republicans into a full-scale panic. His willingness to make false statements or to play around with facts involving matters of national security has generated immense criticism.

There is even some evidence that his inner circle of advisers, including Paul Manafort, doesn’t feel that they have control about what he says when in front of the crowds and the camera. In a new Washington Post/ABC News poll, only 33 percent said Trump has the “kind of personality and temperament” to serve effectively as president, compared to 59 percent for Clinton.

Julian Zelizer

There are many things that we don’t really learn on the campaign trail. Candidates make all sorts of policy promises that will never come true. They present portraits of themselves and their families that are often at odds with their private reality. They talk about new eras of civility and bipartisanship that have no chance of surviving the realities of a polarized Washington. The organizational and strategic challenges of campaigning are very different than those of governing.

But there is one lasting characteristic of a candidate that does become apparent as presidential campaigns drag on, and that is their temperament. The way that candidates respond to the immense pressures of the campaign trail and the way that they do or don’t withstand the inevitable onslaught of attacks that they face from their opposition gives us a very good glimpse into what kind of person we would be electing to this job.

And temperament matters in a presidency. Having a good temperament, being able to remain constrained in the public eye, showing good judgment on how to speak about adversaries and allies, being able to contain moments of anger and outrage that will be a key part of four years in the White House, making certain you know the facts before making potentially provocative statements – all of this matters very much.

Temperament is essential to successful diplomacy. The words that a president says in public and private have a huge effect. Many of the more successful moments for presidents have taken place when they chose to use the right words rather than rely on bluster in moments of crisis.