From the AP:
Former Rep. Joseph P. Kennedy II, the eldest son of Robert F. Kennedy, announced Monday he would not run for the U.S. Senate seat held for nearly 50 years by his late uncle, Edward M. Kennedy. ...
The decision is expected to widen the field of announced candidates for Kennedy's seat. It became vacant Aug. 25, when the senator died of brain cancer at age 77.
Three veteran Massachusetts congressmen - Reps. Michael Capuano, Edward J. Markey and John Tierney - have said they are considering campaigns but would not run against a member of the Kennedy family. The senator's widow, Vicki, had previously ruled out a campaign.
Now the floodgates will likely open. I just hope Marty Meehan decides to stay put. On the other side of the aisle, former Lt. Gov. and 2006 Republican gubernatorial nominee Kerry Healey has also said she won't run.
http://www.swingstateproject.com/diary/5539/masen-joe-kennedy-wont-run