WASHINGTON — President Trump stood by national security adviser Mike Waltz on Tuesday, one day after he was revealed to have looped in the Atlantic magazine’s editor-in-chief on deliberations about striking the Houthis in Yemen earlier this month.

“Michael Waltz has learned a lesson, and he’s a good man,” the president told NBC News in a brief interview Tuesday morning.

Trump, 78, added that the addition of Jeffrey Goldberg to a Signal group that included Vice President JD Vance, Defense Secretary Pete Hegseth, and Secretary of State Marco Rubio had “no impact at all” on the outcome of the March 15 airstrikes, which the president described as “perfectly successful.”

“The only glitch in two months,” the president said, “and it turned out not to be a serious one.”

In the afternoon, during a White House event with ambassador nominees that Waltz attended, Trump told reporters that his national security team was “an amazing group” that would remain intact, saying “you have to learn from every experience.”

The president confirmed that there would be an investigation into the use of Signal, which Trump admitted he was unfamiliar with except for knowing of its use by “a lot of people in the government” including “a lot of the military” as well as members of the media.

“There was no classified information, as I understand it,” Trump defended further.

Speculation had been rampant since Goldberg revealed his participation in the group chat Monday that the snafu would cost the former Florida congressman his job, but the White House has repeatedly expressed confidence in Waltz’s ability.

Press secretary Karoline Leavitt put out a separate statement Tuesday morning downplaying the severity of the group chat leak, claiming no “war plans” or “classified documents” were sent to the Signal channel. 

“The White House Counsel’s Office has provided guidance on a number of different platforms for President Trump’s top officials to communicate as safely and efficiently as possible,” Leavitt wrote on X.

Theresa Payton, a former chief information officer in the George W. Bush White House, told The Post the private encrypted chat’s contents referenced in media reports didn’t rise to “the level of a classified memo.”

Payton, who runs the cybersecurity firm Fortalice Solutions, added that the federal government should consider upgrading to a new intergovernmental platform from Signal.

Trump, at the White House, indicated that no lower-staff will be fired if they were found to have included Goldberg in the group chat. 

“It was one of Michael’s people on the phone,” the president explained to NBC News when asked about Goldberg’s inclusion. “A staffer had his number on there.”

Not everyone in the administration was so sanguine about the situation, with one source telling The Post Tuesday that Waltz was “getting heat” over accidentally inviting the journalist to the group chat and adding the security adviser’s job status was an open question among White House staff.

“Obviously, this is forcing him to answer for what happened,” another source said Tuesday of Waltz. 

Sen. Mark Warner (D-Va.), the vice chairman of the Senate Intelligence Committee, tweeted Tuesday that both Waltz and Hegseth should resign, writing on X: “When the stakes are this high, incompetence is not an option.”

However, another administration source familiar with the matter insisted that “Trump knows not to give an inch to left-wing radicals. They just want a scalp, and if he gives them his NSA, they’ll just move on to his cabinet.”

Goldberg’s bombshell story revealed that he had connected with Waltz on Signal March 11 and was added to a chat called “Houthi PC small group,” filled with top administration officials, two days later.

The likeliest explanation for Goldberg being included on the channel was his Signal profile name “JG” —the same initials as US Trade Representative Jamieson Greer, who often attends National Security Council meetings.

In an appearance on MSNBC’s “Morning Joe” on Tuesday, Goldberg struggled to explain how he had popped up in Waltz’s phone as a suggested contact. 

“I would say that I don’t know Mike Waltz. I think I’ve met him twice. I think I met him at a conference or a party, at a conference a couple of years ago. And then maybe four or five, I forgot when he got to Congress [2019], but four or five years ago. I don’t know him,” he said.

“It struck me as somewhat unusual because we all — and I in particular — have a somewhat contentious relationship with some people in the Trump administration, namely Trump. And so it’s a little bit odd, but why wouldn’t the national security adviser want to talk to a magazine editor, a magazine that covers national security issues?”

Waltz told reporters Tuesday afternoon that he had “never communicated” and “never met” Goldberg.

“There’s a lot of journalists in this city who have made big names for themselves making up lies about this president,” added Waltz, who said officials were “reviewing how the heck [Goldberg] got into this room.”

The messages revealed by Goldberg Monday showed Vance was particularly doubtful about the operation, expressing disagreement with Trump.

“[Three] percent of US trade runs through the [Suez Canal]. 40 percent of European trade does,” said the veep. “There is a real risk that the public doesn’t understand this or why it’s necessary. The strongest reason to do this is, as POTUS said, to send a message.”

“I am not sure the president is aware how inconsistent this is with his message on Europe right now,” Vance went on. “There’s a further risk that we see a moderate to severe spike in oil prices. I am willing to support the consensus of the team and keep these concerns to myself. But there is a strong argument for delaying this a month, doing the messaging work on why this matters, seeing where the economy is, etc.”

During his first term, Trump went through four permanent national security advisers — Michael Flynn, H.R. McMaster, John Bolton, and Robert O’Brien.

Flynn lasted just 24 days in the job before resigning after admitting that he had lied to Vice President Mike Pence about conversations with then-Russian ambassador to the US Sergey Kislyak.