Originally shown to critical acclaim in 1992, this in-depth portrait of America’s most admired and despised political dynasty has been pared from four hours to three, but retains its epic sweep. Its thesis—that John, Robert, and Edward Kennedy were bred to be instruments of the frustrated ambitions of their indomitable father, Joseph—remains just as valid, and its tragic poignancy has only deepened with time. Among the remarkable array of friends, contemporaries, and experts who comment on the family’s saga are John Kenneth Galbraith, William F. Buckley Jr., Tip O’Neill, Ted Sorensen, and Pamela Churchill Harriman. Monday, May, 18, at 9 p.m., PBS; check local listings