And in a head-to-head matchup, Kennedy’s advantage would grow even larger: 14 percentage points — 42 percent to 28 percent. He would best Markey in every age group and across wide geographic swaths of the state.

Kennedy would lead a five-person field by 9 percentage points, 35 percent to Markey’s 26 percent, according to a survey of likely 2020 Democratic primary voters conducted by the Suffolk University Political Research Center.

Buoyed by youth and a dynastic name, Representative Joseph P. Kennedy III would hold an immediate edge over Senator Edward J. Markey should the 38-year-old congressman launch a primary challenge to the seasoned incumbent, according to a new Suffolk University/Boston Globe poll.


One of the poll respondents, Erin Callahan, 32, said she likes Markey and views him similarly to Kennedy politically. But she said she was moved by Kennedy’s nationally televised response to the State of the Union last year, especially his theme of rejecting false choices.

“I remember watching the speech and thinking, ‘Wow, that’s what I wanted to hear,’ ” said Callahan, a Holyoke real estate agent who grew up on Martha’s Vineyard. “I just like him as a politician. I think if he was named something else, I would still like him.”

Still, the survey found that Kennedy’s lead is, in part, owed to his famous surname, and also to the belief that he will be a better adversary to President Trump, and the desire of some voters to install a fresh, younger voice in place of the 73-year-old Markey, who has served on Capitol Hill since 1976.

“To me, it flips on its head the normal incumbent-versus-challenger axiom,” said poll director David Paleologos, noting it’s usually the challenger who opens trailing in the polls and must persuade undecided voters about why he or she is the better choice.


“Here, you have the opposite,” he said. “If you’re Ed Markey, you have to present a compelling reason to be returned to the Senate.”

To be sure, much is still unsettled with more than a year until the September 2020 primary, especially whether Kennedy, who is publicly weighing a run, ultimately launches a campaign.

More than 36 percent of voters say they’re also undecided about whom to pick should Kennedy join a field that includes lesser-known declared challengers in labor attorney Shannon Liss-Riordan , businessman Steve Pemberton, and Allen R. Waters, a former Republican. None of the three polled higher than 1 percent, and Waters has yet to file key paperwork with federal officials, campaign finance records show.

It’s the showdown between Markey and Kennedy, however, that would make the race a high-profile, generational fight, and one of the most closely watched congressional primaries in the country.

Both are popular, well-known entities, with 73 percent of polled voters saying they have a favorable view of Kennedy and 59 percent for Markey. Fewer than 4 percent of voters say they have never heard of either.

But there are a range of factors that begin to separate the two respected, liberal lawmakers in voters’ minds, according to the poll.

More voters view Kennedy than Markey as a better adversary to Trump (45 percent to 23 percent), and a better fighter for Democratic values (43 percent to 25 percent). Asked who is the more liberal candidate, 42 percent said Kennedy, while 24 percent said Markey.


Two-thirds of voters said Markey’s and Kennedy’s ages would not influence their decision. But, about 26 percent of those surveyed said Kennedy’s age and relatively short career in Washington — he is in his fourth term in the House — make them more likely to back him. Conversely, 21 percent say they’re less likely to vote for Markey because he’s a septuagenarian who has spent the last four-plus decades in Congress.

Markey was elected to the House of Representatives in 1976 and served there until he won a special Senate election in 2013 for the seat that had been held by John Kerry.

Kennedy, for his part, won a 2012 race for the congressional seat formerly held by Barney Frank.

Then there’s the Kennedy name, the most famous of Massachusetts’ political dynasties. Nearly 64 percent of voters say they attach positive feelings to the Kennedys — none more so than among those 65 and older, where 75 percent of voters view the name positively, compared with just 2 percent negatively, according to the poll.

In that age bracket, Kennedy tops Markey by 7 points in the hypothetical five-person Senate race.

LaMar Cook, a 38-year-old Democrat who is running for Springfield City Council, told pollsters that he would vote for Kennedy because he feels it’s time to usher in a new era for the Massachusetts delegation.

“Markey has been in Congress since the 1970s and not much has happened on this side of the state,” Cook told the Globe. “I think a lot of folks, especially in the western part of the state, consider him an empty seat.


“It’s time for fresh blood,” he added. Kennedy “has the name, he has the stamina. I think he can stay after Trump.”

Kennedy’s potential challenge of Markey may be part of a growing trend, especially within the Democratic Party, of younger candidates willing to buck tradition and wage intraparty fights against established incumbents. In Massachusetts, Representative Ayanna Pressley embodied that movement in 2018, and Kennedy, in confirming his interest in the race, nodded to it, saying, “I’m not sure this is a moment for waiting.”

That doesn’t sit well with everyone, however. Ian Reid — a Newton Democrat who has voted for Kennedy in his House district that runs from Brookline to Fall River — said he would back Markey for Senate because, simply, “he’s doing a good job.”

“At some point, I’d be happy to vote for [Kennedy] as a senator,” said Reid, 66. “But it’s unseemly for Joe Kennedy to go up against him at this point. We have more important battles than fighting amongst ourselves.”

The poll, which has a margin of error of plus or minus 4.4 percentage points, also found that the state’s Democratic voters are beginning to view the 2020 presidential primary as a two-candidate race between Massachusetts Senator Elizabeth Warren and former vice president Joe Biden.

Biden polled at 26 percent, followed by Warren at 24 percent. No other candidate crept into double digits, with Senator Bernie Sanders of Vermont the closest at 8 percent. About 25 percent of voters said they are still undecided ahead of the state’s March 2020 presidential primary.


Likely Democratic primary voters also said they think highly of Charlie Baker, the state’s Republican governor. Baker is viewed favorably by 61 percent of voters, compared with 19 percent who have an unfavorable opinion of him.

The poll was conducted from Tuesday to Thursday. Callers asked registered voters how likely they are to cast a ballot in the 2020 state primary, and the poll only included respondents who said they were somewhat or very likely to go to the polls.

Matt Stout can be reached at matt.stout@globe.com. Follow him on Twitter @mattpstout.