Trump names Marco Rubio as National Security Adviser and nominates Mike Waltz as UN ambassador

US President makes the announcement on his Truth Social platform

Marco Rubio, left, has been given two top national security jobs at once; Mike Waltz, right, former US national security adviser, is set to become UN ambassador. Reuters; AP

US President Donald Trump on Thursday gave Secretary of State Marco Rubio a second role as his interim National Security Adviser, and nominated the man he is replacing, Mike Waltz, as ambassador to the UN.

The moves mark the first reshuffle in Mr Trump’s Cabinet since he took office in January and come after a national security scandal involving the clumsy handling of US plans to attack the Houthi rebels in Yemen.

Mr Trump's selection of Mr Rubio to temporarily replace Mr Waltz will mean it is the first time since Henry Kissinger in the 1970s that the same person worked simultaneously as secretary of state and national security adviser.

"When I have a problem, I call up Marco. He gets it solved," Mr Trump said at a White House event on Thursday.

He also paid tribute to Mr Waltz, saying on Truth Social he had "worked hard to put our nation’s interests first. I know he will do the same in his new role".

Mr Trump this week completed his first 100 days. Mr Waltz's departure, along with that of his deputy Alex Wong, comes after Mr Waltz's office inadvertently added a journalist to a Signal chat in which high-level US officials discussed plans to strike the Houthis.

After the incident, Mr Waltz took responsibility for creating the group, and insisted that he did not know the journalist or how he ended up in the chat. The Signal chat, the non-sensitive contents of which were made public by The Atlantic, also showed Defence Secretary Pete Hegseth providing a list of times for the strike.

Mr Trump stood by Mr Waltz and the White House insisted that no classified information was shared and no harm inflicted on American citizens. Mr Waltz later faced additional criticism following reports he used Gmail to discuss government business.

The President previously nominated congresswoman Elise Stefanik to be UN ambassador, but her nomination was withdrawn as Republicans were concerned that her leaving Congress, where the party has a tight majority, would put them in a vulnerable position.

Karen Hult, professor of political science at Virginia Tech's Centre for Public Administration and Policy, said Mr Waltz's appointment solves two problems: it fills the gap left after Ms Stefanik's name was removed and it takes away a source of criticism over the Signal incident.

"Meanwhile, as long as Secretary Rubio remains the Secretary of State and serves as the 'acting' national security adviser, it technically is not a demotion but rather an increase in access to the President," she told The National.

"'Acting' officials are frequently more responsive to presidential directions and demands, in part in order to keep their positions."

The move to shift Mr Waltz to a different position could indicate some friction in the administration. During a Cabinet meeting on Wednesday, officials praised Mr Trump achievements over the first 100 days, with each agency head sitting behind red hats typically associated with the "Make America Great Again" movement.

Mr Waltz appeared at the Cabinet meeting and paid tribute to the President, saying it was “an honour to serve you in this administration, and I think the world is far better, far safer for it".

"I think the media wants to frame this as a firing," Vice President JD Vance told Fox News later on Thursday, saying Mr Waltz had carried out promised reforms at the National Security Council. "Donald Trump has fired a lot of people. He doesn't give them Senate-confirmed appointments afterward."

But at the UN, Mr Waltz will be implementing instructions as opposed to co-ordinating policy, Brian Katulis of the Washington-based Middle East Institute told The National.

"It keeps him in the tent. If he's outside the tent, he might tell more stories," Mr Katulis said.

Meanwhile, as both Secretary of State and National Security Adviser, Mr Rubio will have a full plate. He is also the interim leader of the US Agency of International Development, which the Trump administration has cut down significantly amid a rethink over continuing foreign aid.

But Mr Rubio has been oddly sidelined when it comes to the biggest and flashiest foreign policy files such as the Israel-Gaza war, Iran nuclear negotiations or the conflict in Ukraine. Instead, White House special envoy Steve Witkoff has usually been leading US delegations to talks and negotiations.

Mr Katulis said the biggest qualification needed to be in the Trump administration was to be a "chameleon".

"It's to not have an inner core, and it's to just shape-shift or change your colours according to what the big boss wants: loyalty, loyalty, loyalty," he said.

Mr Trump's first term was marked by significant tumult as he went through four national security advisers, four White House chiefs of staff and two secretaries of state.

Democrats have seized on the switches and claimed that Mr Trump is prone to "chaos" and "incompetence".