For most of the 60-year history of the Kennedy dynasty, it’s been easier to imagine its last act as coming in a burst of triumph, a spasm of violence or a dream-shall-never-die promise of enduring hope. On Tuesday, however, what might be the final note of this political symphony was written not in glory or tragedy, but in numbers, the sad prose of politics.

Sen. Ed Markey 55.6 percent, U.S. Rep. Joseph P. Kennedy III 44.4 percent.

In a Democratic primary. In Massachusetts.

The 74-year-old Markey, who was first elected to the House in 1972, was supposed to be the type of proud, uncharismatic incumbent whom Kennedys routinely dispatch to retirement homes or ambassadorships. Joe Kennedy’s grandfather, Robert, famously ended the 18-year political career of New York Sen. Kenneth Keating, a 64-year-old Rockefeller Republican, without even moving to the state until shortly before the election. In a 1962 debate, Massachusetts Attorney General Edward J. “Eddie” McCormack Jr. told political neophyte Edward Moore Kennedy that if his name had been Edward Moore, his Senate candidacy “would be a joke.” The joke, of course, was on Eddie McCormack, who lost the Democratic primary, 69-30.