For the best part of an hour, Mr Trump rambled through a long list of congratulations aimed at his closest advisers, cabinet members and dozens of the business leaders gathered at his feet.
The list included some of the world’s biggest financial, industrial and technology companies, including News Ltd, which was represented by chief executive Robert Thomson – prompting Mr Trump to say: “Where’s Rupert (Murdoch)?”
“I can’t believe Rupert’s not here. He’s the greatest.”
“Most of you, I can say, you’re doing fantastically well,” Mr Trump told the business leaders, whose ranks also included the CEO’s of UPS, AIG, JPMorgan Chase, Dow Chemical and ConocoPhillips and close adviser Stephen Schwarzman, founder of Blackstone.
“Thank you Mr President,” the President said.
As China’s delegation, led by vice premier Liu He stood in stony-faced silence, America’s TV networks gradually tired of the spectacle, switching their coverage away to moves in the House to begin shifting articles of impeachment to the Senate.
After almost an hour, the Chinese vice premier was invited to read out a message from President Xi Jinping, in which he applauded the negotiations.
“It also shows that our two countries have the ability to act on… equality and mutual respect.”
“In the next step the two sides need to implement the agreement… and optimise the positive impact so as to make even greater progress in China- US economic cooperation,” Mr Xi’s letter stated.
“I hope the US side will treat fairly Chinese companies and their regular trade and investment activities.”
Mr Trump said he would be going to China in the “not too distant” future to “reciprocate” Wednesday’s signing.
“It should have happened 25 years ago,” he said of the deal, which he said represents a “sea change” in global trade.
“This really is a landmark agreement,” Mr Trump said, before quipping in an aside to his son-in-law Jared Kushner that this is “harder than New York” property dealmaking.
Mr Trump also noted that while the two year negotiations had triggered market falls – more than $US1 trillion in one day in August – since his arrival in the White House there have been “141 days where we had all-time” highs, he said.
The stock “market is up substantially today”, he said.
The S&P 500 and the Dow Jones indexes set new record highs in early trading after White House economic adviser Larry Kudlow said negotiations on a phase two deal would begin soon.
“China will open itself even wider,” Mr Liu said.
After more than an hour, Mr Trump and Mr Liu sat down to sign the deal.