Rep. Edward J. Markey (D-Mass.) and his wife, Susan Blumenthal, greet well-wishers in Boston on Tuesday after Markey won the Democratic primary for the special U.S. Senate election. (Elise Amendola/ASSOCIATED PRESS)

Two weeks after the Boston Marathon bombing served as a reminder of the unique role that this city and Massachusetts play in the American story, primary voters went to the polls this week to choose a successor to John F. Kerry in the Senate.

In the June 25 general election, the choice will be between Rep. Edward J. Markey (D-Mass.), the dean of the state’s congressional delegation, and Republican newcomer Gabriel Gomez, a private-equity investor and former Navy SEAL.

But Bay State voters may not be picking a senator so much as anointing an heir to a tradition of activism that runs through Kerry and the late Edward M. Kennedy, all the way back to Charles Sumner and Daniel Webster.

“Massachusetts has always punched well above its political weight,” said Rep. Richard E. Neal (D-Mass.). “When you consider people who have served in the United States Senate from Massachusetts, or former House speakers John McCormack and Tip O’Neill, I think it’s clear that the state produces a lot of very effective political figures.”

Kennedy devoted his career to fighting for health-care reform, only to die before Congress enacted changes in his name. Kerry came to the Senate with a reputation as an antiwar activist and spent almost three decades in the Senate focused on foreign affairs. He won his party’s nomination for president in 2004 and now serves as secretary of state.

More recently, Sen. Elizabeth Warren (D) has emerged as a consumer crusader and is already discussed as a future presidential candidate.

In the current race, the heir will either be a long-in-waiting veteran Democrat or a young GOP upstart. Their showdown may be a reminiscent of the contest to replace Kennedy three years ago when Republican Scott Brown faced off with Democrat Martha Coakley, the state’s attorney general, in a special election.

Brown trounced Coakley, delivering a high-profile rebuke to President Obama at the height of the debate over health-care reform, and a stinging defeat for Massachusetts Democrats.

Not this time, Markey vows. “Right now, the Democratic Party in Massachusetts is not agonizing, it’s organizing. They are ready to go,” he said Wednesday.

During a Democratic “Unity Breakfast” at a downtown Boston hotel, Markey stood alongside Rep. Stephen F. Lynch, whom he defeated in Tuesday’s primary.

“We are committed to ensuring that the Republicans do not win this seat in Massachusetts in the same way that they did in 2010,” Markey said, referring to Brown’s victory. “We are going to stand shoulder to shoulder as a united party, working from this morning all the way through to June 25 to ensure that every door is rung, every phone call is made so that people understand the differences between our two parties.”

Assuming the role of attack dog, Lynch blasted Senate Republicans on blocking legislation widely supported by Americans, including the recent bipartisan proposal on expanding the national gun background-check system.

“If you want more of that, then go ahead and put another log in the logjam and put another Republican in the Senate,” Lynch said.

GOP newcomer’s pledge

With Gomez a relative unknown to Massachusetts voters, Markey hopes to paint him as an inexperienced candidate boosted primarily by outside forces. Gomez has declined to take the “People’s Pledge,” a vow Brown and Warren took during their 2012 campaigns to reject financial support from outside groups.

“I’m taking one pledge and one pledge only: to protect and defend the Constitution. That’s the pledge I made when defending my country, that’s the pledge my mother and father made when they came here from Colombia, and that’s my pledge to the people of Massachusetts,” Gomez said in a statement.

Markey has accepted more than $3 million from out-of-state super PACs and did not rule out abandoning his own pledge if Gomez continues to accept outside support. “I believe that in order to do this correctly, you need to two people to take the People’s Pledge,” he said.

Gomez, who was unavailable for an interview Wednesday, hopes to paint a generational contrast between a 37-year congressman and a political novice. He joked during his speech that he was still playing Little League baseball in 1976 — the year that Markey first went to Washington.

“If you’re looking for an experienced, slick-talking politician, I’m definitely not your guy,” Gomez said Tuesday night. “If you’re looking for an independent voice, a new kind of Republican, take a look at our campaign and I’d welcome your support.”

Markey’s longtime goal

Picking up on the attack line, the National Republican Senatorial Committee noted Wednesday that Elvis Presley was still touring and former Boston Celtics player Larry Bird was a freshman in college when Markey won his seat in Congress.

“This campaign will be a choice of the past versus the future,” the NRSC said in a statement.

The Democratic advantage in Massachusetts makes Markey the favorite, but there is acknowledgment that if he wins, he probably would have a relatively short period, by Massachusetts standards, to make his mark, nothing like Kennedy’s 42 years or Kerry’s 28 years.

Neal said he remembers teasing Markey about his long ambition to be a senator. “I was also fairly candid with him that this prospect might not come again,” Neal said. “There’s the reality that if he had not done this [now], it was likely that that path would have been foreclosed.”

Before Markey appeared alongside Lynch on Wednesday, they had to make peace. Lynch had launched his primary campaign against the wishes of national Democrats, but Gov. Deval L. Patrick (D) said that he should have a chance to run.

Before the unity breakfast, Markey, Lynch and Patrick stepped into an adjoining bar for a brief conversation.

The name of the bar was the Last Hurrah.

Paul Kane and Scott Clement contributed to this report.

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