Kennedy signed National Security Action Memorandum 263, he was assassinated a month later.

President John F. Kennedy signed National Security Action Memorandum 263 on October 11, 1963, to develop troop withdrawal plans from the Vietnam War. However, he was assassinated a month later.

Following Kennedy's assassination, President Lyndon B. Johnson escalated U.S. military involvement in Vietnam significantly, leading to a substantial increase in troop levels and a protracted war that lasted for years.