Johnson also faced trouble from Robert F. Kennedy , President Kennedy 's younger brother and the U.S. Attorney General . Kennedy and Johnson 's relationship was troubled from the time Robert Kennedy was a Senate staffer . Then-Majority Leader Johnson surmised that Kennedy 's hostility was the direct result of the fact that Johnson frequently recounted a story that embarrassed Kennedy 's father , Joseph P. Kennedy , the ambassador to the United Kingdom . According to his recounting , Johnson and President Franklin D. Roosevelt misled the ambassador , upon a return visit to the United States , to believe that Roosevelt wished to meet in Washington for friendly purposes ; in fact Roosevelt planned to — and did — fire the ambassador , due to the ambassador 's well publicized views . The Johnson – Kennedy hostility was rendered mutual in the 1960 primaries and the 1960 Democratic National Convention , when Robert Kennedy had tried to prevent Johnson from becoming his brother 's running mate , a move that deeply embittered both men
1960 Democratic National Convention
1960 Democratic National Convention
1964 United States presidential election