Republican presidential candidate Donald Trump holds up his book “The Art of the Deal,” on Nov. 21, 2015, in Birmingham, Ala. (Eric Schultz/AP)

This article has been updated in the wake of the deal to reopen the government.

We probably don’t need to spend much time walking through the extent to which Donald Trump predicated his candidacy on his dealmaking ability. Two excerpts from the day he threw his hat in the ring will suffice.

“If you can’t make a good deal with a politician,” he said in June 2015, “then there’s something wrong with you. You’re certainly not very good. And that’s what we have representing us. They will never make America great again. They don’t even have a chance.”

And, a bit more on the nose: “Our country needs a truly great leader, and we need a truly great leader now. We need a leader that wrote ‘The Art of the Deal.’ ”

This was the case Trump made to the American public: We’re getting beaten, and it will take a business-savvy outsider who knows how to make good deals to fix things.

As president, Trump’s had several opportunities to demonstrate his skills in that regard. He has yet to actually do so.

No example is more stark than the government shutdown, which reached its conclusion on its third day. This is the sort of high-stakes negotiation in which it would seem that Trump would thrive. Instead, news reports suggest that the president has mostly been sidelined.

Why? It’s important to remember that there are at least four ways in which Trump’s self-professed skill at dealmaking doesn’t translate to his position.

1. There’s no walking away from the problem.

In the private sector, deals were largely optional. If Trump was trying to figure out whether to license his name for a property, he could always simply let the deal die. “Know when to walk away from the table,” he wrote in “Art of the Deal.”

There’s no walking away from government funding. It has to be resolved, one way or the other. Walking away from negotiations in the private sector is a chit that can be played to leverage concessions from an opponent. In this case, that’s not an option. You can decide against signing a contract to call a golf course the Trump National in Wherever. You can’t decide against running the government.

In a statement released Saturday at midnight, the White House insisted that negotiations would be stopped.

“When Democrats start paying our armed forces and first responders we will reopen negotiations on immigration reform,” it read. This is as close as Trump could get to walking away — but negotiations simply continued anyway between the two sides on Capitol Hill.

2. He doesn’t have experience negotiating competing interests.

In the private sector, Trump’s negotiations were between the Trump Organization and another party. It wasn’t his job to advocate for third parties or to seek compromises that included meeting the needs of multiple other interests.

As president, there are very few one-on-one negotiations of the sort that Trump’s used to. He’s tried to reshape international diplomacy to focus on bilateral agreements, often with embarrassing results. In March of last year, German Chancellor Angela Merkel had to repeatedly remind Trump that he couldn’t negotiate an agreement with Germany alone because it was part of the European Union. Trump repeatedly made the request anyway.

When he arrived at the Iowa State Fair in 2015, he was asked how he would manage the 535 competing interests in the House and Senate were he elected president. How would he get what he wanted out of Congress?

His response? That he’d do it the same way that he got things approved by the zoning board in New York City. This is his “If you can’t make a good deal with a politician then there’s something wrong with you” argument.

The analogy there is miles from reality. Trump vs. the zoning board is a 1-on-1 negotiation for Trump to get what he wants. Congress is Trump having to get 230-odd representatives and 60 senators representing most of the United States agreed to a unified piece of legislation. To the extent that Trump’s interests are represented, its in the partisan agreement of Republicans on Capitol Hill. As he saw in the health-care debate, though, partisanship isn’t enough to create a bilateral negotiation: Moderate Republicans were enough to block the Senate’s Affordable Care Act overhaul bill last July.

3. In political fights, positions are cemented by core principles.

When Trump is negotiating a licensing deal, there’s no moral component to it. It is literally transactional: You get to use my name, I get your money. Perhaps he doesn’t want the Trump name to appear on a garbage dump, and he’ll draw the line there, but, while there is certainly some bottom line to a negotiation, there’s no deeply held conviction that Trump must defend.

In politics, that’s not the case.

At the center of the shutdown fight is protection for immigrants who came to the country illegally as children. Trump rescinded a policy introduced by the Obama administration (Deferred Action for Childhood Arrivals, or DACA) that would allow those immigrants to live and work in the United States, promising that he’d help reach a deal to address their uncertain status.

For many Democrats, protecting those immigrants is a critical fight, demonstrating the party’s commitment to immigrants — and the Hispanic community — in the face of hostility from their opponents. (What’s more, it’s broadly popular as a policy.) For many Republicans, illegal immigration in any form is anathema, and, regardless of how and why those immigrants got here, it’s unfair to allow them to remain.

You can’t simply give the Democrats $5 billion in funding for some measure to offset their defense of those immigrants. That makes negotiations much more complicated than the sorts of deals Trump is used to working on.

4. Trump doesn’t have solid positions on important subjects.

While many on Capitol Hill have clearly articulated principles guiding what they want to see happen in this fight, Trump doesn’t.

On the campaign trail, he was disdainful of the idea that he should have thought-out policy proposals, dismissing white papers as something that only the media cared about. Such documents are useful, though, both because they force a candidate to understand issues that may be unfamiliar and because they serve as guideposts for negotiating partners.

The extent of Trump’s views on the issue of immigrants who came to the country illegally as children seems to be that he both wants to be a hard-liner on illegal immigration but also doesn’t want to seem mean on this particular issue. As the issue of those immigrants — “dreamers” in the vernacular — has become central to the shutdown, it’s become clear that Trump can go (and has gone) either way on an outcome.

This is hugely problematic because Trump’s position is now the Republican Party position. Trump is supposed to provide leadership on the party’s position and advocate for it — hard to do when your position is a coin-toss. (Or, worse, when it’s informed by whomever you spoke with last.)

The New York Times, writing about Trump’s lack of an anchored position on immigration, quoted former aide Sam Nunberg who framed Trump’s flexibility as an advantage.

“The misconception is that the president does not know what he does not know. In my experience, the reality is that the president knows what he does not know and does not think he needs to know it,” said Nunberg, a former campaign adviser. “He’s a CEO. The tiny details are for his staff.”

In this case, the “tiny details” are the critical issue. And since Trump has neither the inclination to engage in this fight and no central principle to defend, those in the White House who do are filling the void.

Trump met with Senate Minority Leader Charles E. Schumer (D-N.Y.) on Friday and appeared to come close to a deal. That deal, though, ran counter to the principles of much of his party, so he was reportedly forced to retract what he’d agreed to. Chief of Staff John F. Kelly — who, it’s important to remember, came to that job from running Trump’s crackdown on those in the country illegally at the Department of Homeland Security — was integral to rolling back Trump’s agreement with Schumer. Aide Stephen Miller, an immigration hard-liner, has been similarly cited as central to the White House’s obstinate position on DACA.

Trump’s inability to adhere to those principles has meant that his own team has isolated him from the process. From The Washington Post’s report on the current state of things:

“After the shutdown began, Trump suppressed his instincts and did not call Schumer, advisers said, and was buoyed by aides doing a full television blitz — a public strategy partially prepared by West Wing officials who were worried that Trump would be inclined to strike a deal quickly if the media coverage turned poor.”

The sentence that precedes that quote reads: “Privately, some of his closest advisers admit the president is an erratic dealmaker who can unexpectedly overturn negotiations like a flimsy coffee table.”

Trump wants a win, independent of what the win looks like. He wants to have and eat his cake on DACA. He wants to sit down with one person and figure out a solution. For all of those reasons, he seems to be unsuited to the moment and unable to solve the current crisis.

We should have seen it coming. After all, Trump told the country that we needed a president who wrote “The Art of the Deal.” The book was largely written by a ghostwriter named Tony Schwartz.

Schwartz is not the president.