US President Donald Trump announced  that he’s nominating Mike Waltz to serve as United States Ambassador to the United Nations, shifting from his role as national security adviser.

In the interim, Secretary of State Marco Rubio will assume the additional responsibility of serving as National Security Advisor while continuing to lead the State Department.
In a post on his social media account ‘Truth Social’, he wrote, “I am pleased to announce that I will be nominating Mike Waltz to be the next United States Ambassador to the United Nations. From his time in uniform on the battlefield, in Congress, and, as my National Security Advisor, Mike Waltz has worked hard to put our Nation’s Interests first. I know he will do the same in his new role.”
“In the interim, Secretary of State Marco Rubio will serve as National Security Advisor, while continuing his strong leadership at the State Department. Together, we will continue to fight tirelessly to Make America, and the World, SAFE AGAIN. Thank you for your attention to this matter!” he added.
Trump’s presidency has witnessed significant turnover in the role of National Security Adviser. Michael Flynn, Trump’s first national security adviser, served for just 25 days before resigning amid controversy over his communications with Russia, CNN reported.
Flyn’s replacement, HR McMaster, lasted longer in the role, serving for over 13 months before departing due to personal tensions and differences in style with Trump. Trump announced McMaster’s departure in a post on social media and simultaneously announced John Bolton as his replacement.
According to CNN, Bolton’s tenure as NSA was also short-lived, ending in disagreement with Trump over policy positions. Robert O’Brien took over as National Security Adviser in 2019 and served until the end of Trump’s presidency in 2021, providing relative stability in the role compared to his predecessors.