• Mike Waltz removed as national security adviser amid scrutiny from the Signal chat scandal.
• Trump nominates Waltz for UN ambassador while Marco Rubio steps in as interim national security adviser.
• Waltz's ousting marks a significant shakeup in Trump's administration just over 100 days into his second term.
• Criticism surrounding Waltz's handling of sensitive military communications continues to overshadow his departure.
• The decision follows internal pressures regarding national security and operational transparency.

President Donald Trump has announced a major reshuffling within his administration by nominating Mike Waltz as the next United States Ambassador to the United Nations, following Waltz’s removal as national security adviser, according to multiple sources. This change comes just over 100 days into Trump's second term and amid the fallout from a scandal involving a Signal group chat that included sensitive discussions about military plans against Houthi targets in Yemen, which inadvertently included a journalist, Jeffrey Goldberg, from The Atlantic CBS News, New York Times.

Waltz has been under intense scrutiny for his oversight in the Signal incident, which many viewed as a significant breach of operational security. Although Trump initially defended his national security adviser, it appears that internal pressures and criticisms, particularly from his more hardline supporters, prompted this abrupt transition New York Times, Forbes.

As part of this reshuffle, Marco Rubio, the Secretary of State, will serve as the interim national security adviser, a move not seen since the days of Henry Kissinger. Rubio will now juggle multiple high-profile roles, which raise questions about his ability to effectively manage them all amid ongoing strategic challenges faced by the administration New York Times, CBS News.

Trump expressed confidence in Waltz as he transitions to the UN position, indicating that he had worked hard to put national interests first during his time in the White House. The president's announcement also suggested Waltz may have other opportunities within the administration, including previously considered ambassadorship roles CBS News, New York Times.

This sudden shakeup is reflective of the ongoing challenges within Trump’s national security apparatus, following months of alleged disarray and mixed loyalties among top aides and cabinet members. As Waltz's UN nomination awaits Senate confirmation, concerns surrounding his role during the 'Signalgate' incident remain a point of contention Newsweek, The Hill.