There is an actual art (and science) to deal making. And after three-plus weeks of government shutdown, it should be clear by now ― if it wasn’t already― that President Donald Trump is uniquely terrible at the practice.

Trump is so out of the ordinary when it comes to negotiation, in fact, that the quarterly published by the Program on Negotiation at Harvard Law School, devoted its latest issue to him. For the first time in the Negotiation Journal’s 35-year history, it’s used a whole issue to talk about a U.S. president.

Due out next week, the Journal drills into the central paradox of Trump and negotiation: The president spent his career positioning himself as the consummate deal-maker. He’s listed as the author, after all, of the “Art of the Deal,” though it was ghost-written. Yet, there’s little evidence he’s actually good at deal-making. Many of his best real-estate deals were actually put in place by George Ross (who handled real estate negotiations), and Roy Cohn, the legendary attorney, was Trump’s original fixer and known for being a brutal negotiator, writes University of Pennsylvania Wharton School professor G. Richard Shell in a piece for the issue.

Without Cohn, who died in 1986, there have been mostly business failures and bankruptcies and lawsuits.

“In the close to 15 years that I’ve been editing the Journal, nobody has used Donald Trump’s the Art of the Deal as a citation in their article. Never. Not once,” said Nancy Waters, the managing editor of the Journal, which is the publication for the Program on Negotiation, a consortium that includes Massachusetts Institute of Technology and Tufts University.

The omission was not out of elitism. Waters said that the publication, which has contributors across disciplines from around the globe, has covered other more pop-culture-esque business books. Trump’s just never turned up.

That may be because Trump’s negotiating style at a base level contradicts all the best practices generally agreed on by experts in negotiation.

“The way he negotiates directly challenges what is almost a half-century of tools and principles and methods that have emerged in the field,” said Joel Cutcher-Gershenfeld, a professor in the Heller School for Social Policy and Management at Brandeis University, who is the editor of the Journal.

To start, Trump claims to use a zero-sum strategy in which he wins and the other side loses. The win-lose equation is considered out of date, ineffective and generally counterproductive among those who study negotiation.

SAUL LOEB via Getty Images Speaker of the House Nancy Pelosi and Senate Democratic Leader Chuck Schumer speak to the media following a meeting with President Donald Trump about the partial government shutdown at the White House in Washington, DC, Jan. 9, 2019.

Win-lose dealmaking is a tough sell in a democracy or anytime you’re trying to reach an agreement with a powerful counterparty who has enough leverage to withstand the demands of the bully across the table, like Speaker of the House Nancy Pelosi (D-Calif.) fresh off her party’s electoral victory in the 2018 elections.

In such cases, you’re not likely going to get exactly what you want. So a good negotiator has to think empathetically about what the other side wants and then sell them a deal that could be viewed as a so-called “win-win.” Trump isn’t known for empathy.

Still, this isn’t complicated. “All the other presidents knew how to make deals,” said Carrie Menkel-Meadow, a professor of Law at the University of California Irvine Law School and a co-editor on the special issue.

“Trump doesn’t understand the basic principle: To get what you want, you have to give other people what they want,” said Menkel-Meadow, who was at Georgetown Law during the Clinton-era shutdown and trained negotiators at the Department of Justice.

A solid deal-maker also doesn’t make an enemy out of his counterparty. Ideally in politics or diplomacy, he’s built up some goodwill with them. Trump, on the other hand, demonizes and belittles his political opponents (and sometimes his allies).

Nancy and Cryin’ Chuck can end the Shutdown in 15 minutes. At this point it has become their, and the Democrats, fault! — Donald J. Trump (@realDonaldTrump) January 14, 2019

Former President Barack Obama used to get criticized for not schmoozing with Republicans in the House. This president, on the other hand, not only isn’t here to make friends, he’s actively terrorizing his colleagues via Twitter.

“What we’re seeing here is the cost of not building a relationship with the Democrats and their leaders, and now when it’s absolutely essential because they’re more powerful and he needs their votes, he’s incapable of doing it,” said Thomas Kochan, a professor at the Massachusetts Institute of Technology’s Sloan School of Management, who wrote about Trump’s effect on business negotiations. “They don’t trust him; he doesn’t trust them.”

Lack of trust is the third critical piece of the failed Trump strategy. Negotiation experts concede that a hard-driving win-lose strategy sometimes can work. But not without trust.

Former President Lyndon Johnson, for example, was known for his hard-driving, persistent, negotiation tactics. And, of course, Johnson was able to push through civil rights legislation at a time when his own party was dominated by segregationists. This was a case of someone staking out a position and forcing everyone to his side.

But one of the key ways Johnson differed from Trump, Cutcher-Gershenfeld pointed out, is trust. “His word was his bond,” he said.

Trump has already famously backed out of immigration deals he’s agreed to.

There may be some upside to Trump’s willingness to break the established norms of negotiating, said Cutcher-Gershenfeld. “I don’t want to say it’s all bad, but I do want to say when you break the rules of the game you should know what you’re doing.” He pointed that in the case of Trump opening talks with North Korea, there could possibly be some upside to the president’s unconventional approach.

The zero-sum strategy and willingness to walk away from the deal may also have been better suited to one-off real-estate transactions. Politics is different. “In negotiations with Congress, when you walk away there isn’t another Congress to walk to,” he said.

Right now, Democrats seem to be just as locked into their position as Trump. On Tuesday, a group from the House declined the president’s offer for a lunch meeting, though there were reports that behind-the-scenes talks were happening.

In the Negotiation Journal’s special issue, 35 experts in negotiation from across a wide range of disciplines ― lawyers, trade negotiators, psychologists, business school professors, political scientists ― examine the effect Trump’s deal-making strategy is having on the world, from international diplomacy to gender and race relations here in the U.S.

Many of the authors have advised both Democratic and Republican policymakers over the years.

The study of conflict resolution really took off during the Cold War when the stakes of failed negotiation and zero-sum gamesmanship were truly apocalyptic: nuclear annihilation. The stakes today seem increasingly high, as well, with Brexit threatening to destabilize the U.K. and Trump’s sketchy diplomacy skills threatening to upend so much else.

Still, many of the experts in the field are true believers in the proposition that there is no dispute too thorny to untangle. Many still believe there’s a path to peace in the Middle East if only the right strategy is employed.

And so, several who spoke with HuffPost did see a way out of the shutdown that didn’t involve the courts. (That’s where you go when negotiations break down, said Menkel-Meadow.)

MIT’s Kochan suggested “reframing” the debate. Instead of making this a fight about a wall, making it a negotiation more broadly about border security. That way there’s more to bargain over ― not just a wall yes or no, but also funds for greater resources. Democrats could argue for support for the Dreamers and a path to citizenship.

He and other experts also recommended bringing in more people to negotiate ― a tried-and-true tactic. Kochan suggested that the president, the Senate and the House should create an expert panel that would figure out a path forward.

Since this is Trump we’re talking about perhaps the key to unlocking the stalemate begins and ends with the president’s perception of himself. “Any solution has to feed his ego,” Kochan said. “As much as it’s painful to play into that.”

Right now, he’s backed himself into a corner and if his opponents truly want to break this impasse they have to help him figure out a way to save face, said Deborah Kolb, a professor emeritus at the Simmons University School of Business in Boston and the author of Negotiating at Work: Turn Small Wins into Big Gains.

“He’s really locked himself in,” she said, adding: Great negotiators just don’t do that.

Clarification: Language in this story has been amended to clarify that it was George Ross who negotiated many of Trump’s real estate deals.