Here come the Kennedys. Again.

Two and a half years after the death of Sen. Ted Kennedy (D-Mass.) and a year after his son Rep. Patrick Kennedy (D-R.I.) retired from Congress, the Kennedy clan looks as though it will attempt a return to national office.

Joe Kennedy III, the 31-year-old grandson of Robert F. Kennedy and son of former Rep. Joe Kennedy (D-Mass.), is forming an exploratory committee for the seat of retiring Rep. Barney Frank (D-Mass.). To do so, Kennedy is reportedly leaving his position as Middlesex County assistant district attorney — a good indication of how serious he is about the race.

Kennedy was seen as one of the more likely Kennedys to make the leap to elective office (see our recap from late 2010 on which Kennedys have been rumored to run for office — “The next Kennedy”), but he opted against running for an open seat in 2010 when Rep. Bill Delahunt (D-Mass.) retired.

His father, the former congressman of the same name, has been mentioned as a potential candidate for Senate. But he declined to run in either the special election to replace Ted Kennedy in 2010 or the 2012 race against the senator’s successor, Republican Scott Brown.

When Patrick Kennedy retired, it was the first time in more than 60 years that a member of the first family of Democratic politics wasn’t in high office in Washington.

It remains to be seen whether Joe Kennedy III will actually win a seat in Congress, though. While he’s running in a safe Democratic district, several other Democrats — including Boston City Councilman Mike Ross and Bristol County District Attorney Sam Sutter — have expressed interest in the seat.