Who succeeded John F. Kennedy as President of the United States?

Under which president did Richard Nixon serve as Vice President? Who was First Lady during Dwight D. Eisenhower's presidency? Mamie Eisenhower was married to which president? Which number president was John F. Kennedy? Who was President immediately before John F. Kennedy? Which political party did President John F. Kennedy belong to? Which president served from 1961 to 1963? In what year did John F. Kennedy first take office as President?