ANALYSIS  — A testy and combative President Donald Trump winged it Friday in the Rose Garden, turning an often-rambling defense of his border security emergency into a 2020 assault on Democrats.

Trump has redefined the presidency around his unique style and penchant for unpredictable and unprecedented moves, as well as the sharp rhetoric he uses both at the White House and his rowdy campaign rallies. But there was something different during Trump’s remarks Friday, with the president leading off his remarks by talking about anything but the compromise funding measure and border security actions he signed later that day.

He lauded his “very good relationship” with North Korean leader Kim Jong Un and touted their second denuclearization summit later this month, even talking up that country’s economic potential. On Chinese President Xi Jinping, again, Trump talked about their rosy relationship and predicted: “We’re a lot closer in this country than we ever were with having a real trade deal” with Beijing — yet he struggled to note specific things that might be in the potential deal.

Out of the blue, and with no teleprompter loaded with prepared remarks, he announced his administration is planning a trade deal with the United Kingdom that amounts to “increasing very substantially” trade between the longtime allies. Back on Kim, he said: “No more rockets going up, no more missiles going up, no more test of nuclear,” even though his own intelligence chiefs say North Korea has not taken steps to dismantle its nuclear programs.

About an hour later came his both-sides-of-the-mouth dismissal of the notion, as NBC News’ Norah O’Donnell asked, that Fox News and conservative personalities are “setting policy.” He also said many conservative television and radio personalities have been “terrific” supporters of both his candidacy and campaign.

[White House: Wall funds would be ‘back-filled’ in 2020 budget request]

For instance, despite noting that conservative commentator Ann Coulter was among the first to predict his 2016 victory, Trump, as he often does, sent mixed signals: “I like her. But she’s off the reservation,” he said to chuckles from the press corps and his own staff who were assembled on the nearby colonnade. Coulter has publicly criticized Trump in recent months for not building the border wall.

Watch: Trump announces national emergency on border, despite likely legal challenge

It was a few minutes before a sun-drenched Trump launched into his usual border security and illegal immigration talking points. He at first appeared flat and frustrated. But he eventually hit his stride — and the uniquely unscripted president fell into campaign mode, turning a venue typically reserved for staid and stately events into a rally.

And it wasn’t long before he launched a string of attacks on congressional Democrats, including two of his favorite targets who are vastly unpopular with his conservative base.

“Nancy knows it. Chuck knows it. They all know it. It’s a big lie. It’s a big con game,” he said of Speaker Nancy Pelosi and Senate Minority Leader Charles E. Schumer, contending that large loads of drugs or humans being trafficked only cross the U.S.-Mexico border in “areas where you don’t have a wall.”

“You don’t have to be very smart to know, you put up a barrier, people … can’t do anything,” Trump said.

He spoke of “monstrous caravans” heading for the U.S.-Mexico border, saying several times he opted to declare a national emergency and issue an executive order to access $6.6 billion in Pentagon and Treasury Department dollars for his border barrier project because “we are talking about an invasion.” (The bipartisan spending measure he signed includes $1.375 billion, taking the total to roughly $8 billion — though court cases are inevitable. One could come from the Democratic leaders he once again slammed.)

But the president did not appear eager at times to stick to the day’s purported topic. Soon, he was back to criticizing Beijing’s trade tactics and touting the U.S. economy’s performance since he took office.

“We’ve picked up … trillions of dollars of worth,” he asserted. “And China’s lost trillions of dollars.” Then he swerved to a preview of a new round of trade talks with Chinese officials next week in Washington.

After briefly getting back on track, Trump opted for another abrupt swipe at Democrats.

“If the opposing party got in, this economy would be down the tubes,” he said, then explaining that his economy means “more people want to come.”

The implication: He needs his wall to keep more of those additional migrants out, and he’s willing to take on Democrats and outside groups in court to build it.

[Legal fight expected for Trump’s national emergency declaration]

And once the president took questions, the campaign rally continued as he lashed out at CNN’s Jim Acosta. “You’re CNN. You’re fake news. You have an agenda,” Trump said. “It’s a fake question.”

And Playboy’s Brian Karem got what has become a Trump press conference staple when the president ordered him to “sit down.”

Above all, Trump’s tone and body language suggested a chief executive who is frustrated after having to take historically extreme measures to merely move a top campaign promise forward.

“I got almost $1.4 billion dollars when I wasn’t supposed to even get one dollar,” Trump said, mocking Pelosi’s statement that she would only give him a buck for the barrier in the spending measure both chambers passed with bipartisan tallies Thursday. “But I’m not happy with it.”

And he clearly knows court challenges of his pending funding shifts are coming. But again, he seemed less confident than he typically does in public.

“Happily, we’ll win,” he said. “I think.”