President Donald Trump says he is nominating national security adviser Mike Waltz as United Nations ambassador while Secretary of State Marco Rubio would take over Waltz’s duties on an interim role.

Mike Waltz, who played a central role in the Signal-gate, is now out as Trump's National Security Advisor, but why did he decide to resign?

Waltz was at the center of the Signal chat controversy, in which a journalist was accidentally included in a discussion of sensitive military information.