A Kennedy-Markey Primary? Massachusetts Is Jolted

“I’m not going to run against Ed Markey,” the mayor said.

Ms. Pressley is also seen as a potential Senate candidate, although Democrats close to her signal that she may wait to run for Senator Elizabeth Warren’s seat — whether in a special election should Ms. Warren be elected president or should she choose to retire in 2024. Then there’s Maura Healey, the Harvard basketball star turned state attorney general, who is widely thought to be eying the governor’s corner office on Beacon Hill but who has also been encouraged to consider taking on Mr. Markey.

The tumult has anguished some longtime Massachusetts politicians, who recall that past primaries here were fought on momentous issues, as when Father Robert Drinan ousted a sitting House Democrat in 1970 over Vietnam.

“I am distressed by it,” said former Representative Barney Frank, calling the primaries “a luxury we should not be indulging in” when Democratic donors and activists could be helping in the presidential race and competitive Senate contests in nearby Maine and New Hampshire.

Mr. Frank, whose seat is now held by Mr. Kennedy, was characteristically blunt when asked about his successor taking on Mr. Markey, his longtime colleague in the House. “I was shocked Joe would do that, I think it’s a mistake,” he said, speculating that Mr. Kennedy was considering a run now because he does not “want the seat to eventually go to anybody else.”

Many Democrats here say they find the plotting by the genial Mr. Kennedy to be out of character. Yet these assumptions also ignore the cutthroat side of the Kennedy family: the congressman’s grandfather, Robert, and his great-uncle, Edward, both challenged sitting Democratic presidents. (Mr. Kennedy declined an interview request.)

And not every Democratic leader here is unsettled by the outbreak of primaries.

“I may be in the minority, but I like the idea of competitive primaries,” said former Gov. Deval Patrick, who claimed the Democratic nomination for the state’s top job as a political outsider. “Every member of our delegation knows that nobody is entitled to these jobs. Competition for office is the way it’s supposed to work.”

Mr. Patrick, who, like many other Democratic officials here, has been lobbied for support by Mr. Markey, said he would stay out of a Kennedy-Markey race. But in an ominous sign for Mr. Markey, other Massachusetts Democrats who have announced their support for him sounded less committed when asked what they would do were Mr. Kennedy to run.