Trump Shakes Up Security Team: Mike Waltz Tapped for UN Ambassador, Rubio to Step In as Interim National Security Adviser

WASHINGTON — In a major reshuffling of his national security team, former President Donald Trump announced Thursday that he is nominating Mike Waltz, his current national security adviser, to serve as the next U.S. ambassador to the United Nations.

Trump’s decision comes amid growing scrutiny of Waltz, who recently faced backlash over a botched Signal chat incident involving classified military discussions. Secretary of State Marco Rubio will temporarily take over Waltz’s national security duties while continuing to lead the State Department.

“From the battlefield to Congress to the White House, Mike Waltz has always put America’s interests first,” Trump wrote on social media. “In the interim, Marco Rubio will continue his strong leadership at State while serving as national security adviser.”

Rubio’s interim appointment echoes a historical precedent — Henry Kissinger held both roles during the Nixon administration. Still, the timing adds complexity, with crises in Ukraine and Gaza, Iran’s nuclear ambitions, and Trump’s ongoing global tariff battles all demanding urgent attention.

It remains unclear how long Rubio will serve in the dual role.

Waltz’s nomination follows a controversy that erupted in March, when The Atlantic revealed he had mistakenly added the magazine’s editor-in-chief, Jeffrey Goldberg, to a Signal group chat discussing a sensitive military operation targeting Houthi militants in Yemen.

Although no classified information was confirmed to have been shared, the error raised red flags within the administration and fueled criticism from Trump-aligned influencers. Far-right activist Laura Loomer celebrated reports of Waltz’s exit online, writing “SCALP” and calling for more dismissals of officials she claims are not loyal to Trump’s “America First” vision.

Despite the uproar, Trump defended Waltz publicly and ultimately gave him what analysts are calling a “soft landing” with the high-profile U.N. nomination.

Waltz now faces a Senate confirmation process that could become a political flashpoint. Democrats are likely to question his handling of the Signal chat and his hawkish foreign policy positions.

“I look forward to a thorough confirmation hearing,” said Sen. Chris Coons, the top Democrat on the Senate Foreign Relations Committee.

Trump is reportedly considering several candidates to permanently replace Waltz as national security adviser. Names in the mix include:

• Steve Witkoff – A longtime Trump ally and real estate executive, currently serving as a special envoy in peace negotiations involving Ukraine, Israel, and Iran.
• Richard Grenell – Trump’s former ambassador to Germany and ex-acting director of national intelligence, who’s also eyeing a run for California governor.
• Sebastian Gorka – National Security Council senior director for counterterrorism.
• Michael Anton – A senior official at the State Department with deep ties to Trump’s first-term foreign policy team.

Witkoff has reportedly expressed reluctance about taking on the demanding adviser role, preferring his current envoy position.

The Signal scandal hasn’t only affected Waltz. Defense Secretary Pete Hegseth is also under investigation by the Pentagon’s inspector general for his own use of the unsecured app.

Hegseth is accused of sharing sensitive information — including aircraft launch times and bombing schedules — in Signal group chats and bypassing Pentagon security by installing a personal computer near classified terminals. Despite bipartisan criticism, Trump has continued to back Hegseth publicly.

Waltz’s elevation to U.N. ambassador — just over 100 days into the new administration — marks a significant shift within Trump’s foreign policy team. While his departure may calm internal tensions, the challenges ahead remain steep as Rubio temporarily juggles two of the most demanding roles in the federal government.