Sources say Kennedy was privately furious at Clinton for her praise of President Lyndon Baines Johnson for getting the 1964 Civil Rights Act accomplished. Jealously guarding the legacy of the Kennedy family dynasty, Senator Kennedy felt Clinton's LBJ comments were an implicit slight of his brother, President John F. Kennedy, who first proposed the landmark civil rights initiative in a famous televised civil rights address in June 1963.
One anonymous source described Kennedy as having a "meltdown" in reaction to Clinton's comments.
It's funny. When I heard Clinton's LBJ quote, I thought she was slighting Martin Luther King (although I know Sean Wilentz disagrees). But I guess Teddy heard something else.