Trump says he plans to move his national security adviser Mike Waltz to the UN

President Trump said on Thursday he is nominating his national security adviser Mike Waltz as his ambassador to the United Nations in the first big shake up of top aides since Trump started his second term.

Trump said on social media that he would make Marco Rubio his interim national security adviser — a role that will come on top of his existing job, Secretary of State.

Waltz will need to be confirmed by the U.S. Senate for the UN position. “I’m deeply honored to continue my service to President Trump and our great nation,” he said on social media.

The UN spot has been vacant since Trump asked his first nominee, Rep. Elise Stefanik, R-N.Y., to instead stay in Congress to help preserve the narrow majority Republicans hold in the House of Representatives.

Waltz has come under pressure since March when he inadvertently invited a journalist into a private text chat among top officials discussing military plans for U.S. strikes on the Houthis in Yemen.

Trump had initially defended Waltz — who took responsibility for the mishap — and downplayed the incident as a “glitch.” He was complimentary of Waltz in his announcement on Thursday, saying he had “worked hard to put our nation’s interests first.”

Trump told The Atlantic in an interview last week that “Waltz is fine” when asked about his future. “I think we learned, ‘Maybe don’t use Signal, okay?’ If you want to know the truth. I would frankly tell these people not to use Signal, although it’s been used by a lot of people.”

But Trump has leaned more heavily on other top aides for national security issues like the conflicts in Ukraine and Gaza, and talks with Iran, including Middle East envoy Steve Witkoff, Treasury Secretary Scott Bessent as well as Secretary of State Marco Rubio.

The announcement came after hours of rumors that Waltz was leaving his position — and while Rubio’s spokeswoman Tammy Bruce was briefing reporters at the State Department. “We have to admit, these last 100 days — it’s like hanging on to a freaking bullet train,” Bruce told reporters.

The last person to simultaneously be Secretary of State and national security adviser was Henry Kissinger, during the Nixon era. He did both jobs for two years.

“Some Americans in Washington and elsewhere thought the double assignment gave Kissinger too much power and persuaded President Ford to strip him of his White House title in late 1975,” presidential historian Michael Beschloss said.

In Rubio’s case, Trump has indicated this will be a temporary assignment until he picks a new national security adviser.

Waltz was the first Green Beret elected to Congress where he served three terms representing east central Florida in the House of Representatives.

Waltz, who was known as a national security hawk, had an uphill road to climb within Trump’s circle. He had long been an advocate of sanctions against Russia and never seemed to fully align with Trump’s approach to Moscow and other adversaries.

Before taking the White House job, Waltz served as chairman of the House Armed Services subcommittee on readiness and was a member of the House Foreign Affairs Committee and the Permanent Select Committee on Intelligence.

NPR diplomatic correspondent Michele Kelemen contributed to this report.