Trump Says John Bolton 'No Longer Needed' At The White House

John Bolton's resignation as National Security Advisor was announced by President Trump via tweets. Trump informed Bolton the previous night that his services were no longer needed. Secretary of State Mike Pompeo and Treasury Secretary Steven Mnuchin addressed the resignation in a press briefing, emphasizing the president's right to choose his staff. Bolton texted political analyst Robert Costa, stating he had resigned. Trump plans to announce Bolton's replacement next week, with Charles Kupperman serving as acting national security advisor in the interim.

What did Bolton state in his text shortly after the announcement?

Who will serve as acting national security advisor following Bolton's resignation?