It was the centrepiece of his presidential campaign.
From Asia to Africa, Europe to South America, everyone knew that Donald J Trump would build a wall on the border with Mexico if he became president of the US.
The world laughed, but the president of the US was adamant.
His supporters lapped it up. “Build That Wall!” they chanted at rallies.
They cheered even louder when he told them there was a sweetener:
American taxpayers would not have to pay a cent for it.
“I would build a great wall, and nobody builds walls better than me, believe me, and I’ll build them very inexpensively,” Trump said in June 2015.
“I will build a great, great wall on our southern border and I’ll have Mexico pay for that wall.”
He became so enamoured of his wall that he decided that it would get a name.
So in August 2015 he declared: “I want it to be so beautiful because maybe someday they’ll call it The Trump Wall.”
The irony in all this talk of a wall was that he had not actually ever thought of building a wall.
It was not a core belief or an old idea of his.
The New York Times recently explained it: “His political advisers landed on the idea of a border wall as a mnemonic device of sorts, a way to make sure their candidate – who hated reading from a script but loved boasting about himself and his talents as a builder – would remember to talk about getting tough on immigration, which was to be a signature issue in his nascent campaign.”
Sam Nunberg, one of Trump’s early political advisers, recalled telling Roger J Stone jnr, another adviser: “How do we get him to continue to talk about immigration?
“We’re going to get him to talk about how he is going to build a wall.”
His conservative audiences loved it. And he loved the applause.
That is how the marriage of Trump and the wall was consummated.
As his scandal-mired tenure meandered on, however, it became clear that the wall wasn’t going to be built. First, Mexico was not going to pay for the wall, as it had repeatedly said years ago.
To save face, he said he did not mean that Mexico would cut him a cheque.
On January 2, he tweeted: “Mexico is paying for the Wall through the new USMCA (formerly Nafta) Trade Deal.”
That was untrue. The trade deal has not passed through Congress, let alone have any clause that binds Mexico to paying for the wall. So Trump played his last card. He shut down the government and dared the Democrats to give him the $5.7bn (R78bn) he wants for the wall.
He did not count on the fact that the Democrats, fresh from an invigorating win in the mid-term elections in November, would stare him down under the leadership of congressional Speaker Nancy Pelosi.
He tried to make a deal, claiming that his knowledge of the “art of the deal” was unmatched.
The shutdown dragged on.
In an attempt to save face, he said he didn’t mean a physical wall but a steel fence or some sort of barrier.
But Congress would not appropriate money for it. It all came to a head during the week.
On Friday, his long-term adviser Stone was charged for allegedly coordinating with WikiLeaks to find damaging information about 2016 presidential competitor Hillary Clinton. After 35 days of no pay, air traffic controllers in New York started going AWOL.
As the news filtered out, causing outrage, Trump conceded – the longest government shutdown in US history was over and negotiations would restart over the wall.
The backlash from fellow Republicans and other right-wing and conservative commentators has been swift and brutal.
Right-wing outrage merchant Ann Coulter said Trump was now the “biggest wimp ever to serve as president of the US”.
Conservative political commentator Peter Wehner said: “In the showdown with Nancy Pelosi, Trump’s been exposed as pitifully weak, all bluster, a pathetic negotiator.
“Pelosi rolled him in every way. Egged on by right-wingers, the whole thing was buffoonish from start to finish.”
The popular impact on Trump and his 2020 presidential run is still unknown although his approval rating has always been low (it’s now at around 36%).
The 800,000 government workers affected by the shutdown will get back pay.
But most security guards, food service employees and millions of other contract workers who keep the US government functioning will not be reimbursed – because they are contract workers.
What their thoughts on this mess are, is anyone’s guess.
Many will shudder at Trump’s language, too, as the very thinskinned president hears his own support base say again and again that he lost a major fight.
He does not like losing. On Thursday, he tweeted: “This was in no way a concession.
“It was taking care of millions of people who were getting badly hurt by the Shutdown with the understanding that in 21 days, if no deal is done, it’s off to the races!”
He is preparing to fight – again. That has implications for the world.