Democratic presidential candidate Hillary Clinton appears on stage at a rally a Fort Hayes Metropolitan Education Center in Columbus, Ohio, on July 31. (Andrew Harnik/AP)

For all our talk of policy, there’s a key Presidential attribute that can’t be sussed out of position papers or stump speeches: temperament. “A president’s temperament is his most important quality,” Slate’s John Dickerson wrote in 2012. Former Defense Secretary Robert Gates agreed, telling MSNBC, “temperament is the most important quality a President needs to have.”

Donald Trump’s deficient temperament is recognized as a big campaign liability (though he, of course, says he has “one of the best temperaments” of any candidate) .  Still, it’s an open question: Who in politics today—besides perhaps our preternaturally calm current president—has the temperament to meet the tumult?  Who is centered, balanced, and grounded enough to think clearly and hold the space even in the face of confusion and chaos?

For most people, Hillary Clinton doesn’t jump to mind. After all, she’s a highly-scripted career politician with a penchant for controversial compromises and a seemingly unrivaled capacity to attract scandal.

But there’s evidence she’s doing something few politicians ever even consider: deliberately training her mind to deal with the demands and uncertainties inherent in high-level public service. She’s actively reshaping her temperament to prepare for the Presidency.

Last fall, when the former secretary of state responded to nearly 11 hours of grating Republican questions in a House Benghazi Committee hearing, many commentators noted her discipline, thoroughness and “unearthly stamina.” When friendly members of Congress  asked her about her secret to staying focused, even-keeled and alert amidst the endless onslaught, an NPR microphone caught her explaining that she practiced meditation during the times in the hearing when she didn’t need to speak.

This wasn’t out of the blue. Clinton has a longstanding interest in meditation practice and mindfulness. As first lady, she was even ridiculed by right-wing talk radio for bringing a contemplative teacher to the White House.

Looking to her calmness and clarity in the marathon Benghazi hearing, it’s easy to imagine the ways that these kinds of centering practices could help, say, in a tense arms control negotiation with Vladimir Putin or in consoling people after a natural disaster.

But there are deeper reasons why meditation — the practice of cultivating focused attention on the present moment –  could be crucial for a modern president.

While meditation is still often portrayed in pop culture as an esoteric art, it’s now common at GoogleApple and the Pentagon. The surprisingly simple practice — stepping back to focus on the breath and notice thoughts and sensations — cannot only help a public servant deal with a stressful situation like a hostile hearing but also to devise strategy and solve problems.

Timothy Wilson, a psychology professor at the University of Virginia, has argued that the human brain is poorly equipped to handle the roughly 11 million bits of information that arrive in any given moment of modern life. For efficiency’s sake, people tend to make decisions based on shortcuts — assumptions and impulses — rather than careful attention to what’s really happening in the moment. Through the practice of meditation, a person can observe and reflect on the assumptions, feelings, and internal storylines that unconsciously guide words and behaviors. According to business gurus like Bill George and Daniel Goleman, meditation is a tool to listen more effectively and act on the basis of real intention rather than habitual patterns or emotional whims.

For the president — a person tasked with absorbing large amounts of information and making sound decisions — these capacities are crucial. Meditation can be a tool for building mental concentration, considering contradictory arguments, and staying open to unexpected information.  Like Steve Jobs made meditation a central part of his work at Apple, a President Clinton could use the practice as a means to enhance awareness and insight.

Of course, Hillary still needs to win in November. And in this regard, her practice can be extremely helpful.  Whether it’s withstanding the psychological attacks Trump will inevitably bring to the debates or remaining calming and collected in the face of the indignities of Fox News, she’ll need serious tools to center herself.

Just the fact that a meditation practitioner is running for president is significant. But it’s especially significant in this particular election year. That’s because Donald Trump is, in so many ways, the absolute antithesis of mindfulness. Trump is emotionally brittle and  dependent on external validation. He is easily distracted and rarely considers the counsel of his closest advisers.  In 2013, Trump offered a quote that sums up his worldview nicely: “Show me someone without an ego, and I’ll show you a loser.”

We’ll see. If Hillary can use her contemplative practice to cultivate the focus, awareness and insight that this moment demands, she can prove his statement dramatically wrong. The biggest ego in the history of American presidential politics could lose in a landslide.