On Friday, Trump announced the end of the shutdown. He also started laying the groundwork for another. Photo: Al Drago/Bloomberg via Getty Images

The longest government shutdown ever hadn’t even ended when Donald Trump began laying the groundwork for another one. Speaking in the White House Rose Garden Friday to announce a deal to fund the government for three weeks, Trump said if he doesn’t have border wall money by February 15, it may be time for another tantrum.

“We really have no choice but to build a powerful wall or steel barrier,” he said. “If we don’t get a fair deal from Congress, the government will either shut down on February 15, or I will use the powers afforded to me under the laws and Constitution of the United States to address this emergency.”

Mick Mulvaney, Trump’s acting chief of staff, made the same threat on CBS’ Face the Nation Sunday. Asked if Trump was prepared to shut down the government again, Mulvaney said, “Yeah, I think he actually is.”

“He is willing to do whatever it takes to secure the border,” Mulvaney said, including compounding the suffering of hundreds of thousands of workers who went unpaid during the shutdown. “He does take this very seriously. This is a serious humanitarian and security crisis.”

Like Trump in the Rose Garden, Mulvaney also floated the possibility of an emergency declaration to build the wall, but it’s clear that there’s little appetite for that in the White House. If there was, Trump would have already done it, and as Mulvaney acknowledged, the legal gridlock that would follow such a move wouldn’t give the White House the clear win it’s after.

Trump himself set the odds for a border-wall deal at less than 50 percent in a Wall Street Journal interview Sunday. Asked about the chances a 17-member congressional board has of hammering out a deal, Trump said, “I personally think it’s less than 50-50.” Would he accept less than his desired $5.7 billion for the wall? “I doubt it. I have to do it right,” he said.

In the interview, Trump also laid out some parameters for the negotiations with Democrats, saying he’s unlikely to trade wall funding for citizenship for Dreamers. As for another shutdown, he said, “It’s certainly an option.”