Markey's six-point edge expands to an eight-point margin — 46 to 38 percent — when undecided voters leaning toward one candidate or the other are included.
"Either way you look at it — with leaners or without leaners — you've got a race within single digits coming out of the primary," says Steve Koczela, president of the MassINC Polling Group, which conducted the survey for WBUR. "You've got a competitive race."
The WBUR poll is in line with a Public Policy Polling (PPP) survey released Friday that showed a tight race — 44 to 40 percent for Markey, a Democrat. But it differs sharply from a Suffolk University/WHDH-TV poll, released Wednesday night, that gives Markey a 52 to 35 percent lead.
Whatever the spread, the WBUR poll suggests plenty of room for movement before Election Day on June 25.
Nearly one in four voters are still undecided. And political newcomer Gomez, if far better known than he was just weeks ago, remains undefined for much of the public.
While 37 percent of poll respondents have a favorable view of Gomez and 16 percent have an unfavorable view, nearly half have no opinion of the candidate or haven't heard of him.
"People are starting to get a sense of who he is; he's not wholly undefined," Koczela says. "But he still has a ways to go in defining himself. And that really cuts both ways, because he'll be trying to define himself and the Markey campaign will be trying to define him."
Messages Not Yet Registering
Gomez, of course, is aiming to define his opponent, too.
After claiming the GOP nomination last week, he immediately set about painting Markey as a tired figure.
In his victory speech, the Republican pointed out that he was still playing Little League baseball and the rock group Boston had just put out its first album when Markey was first elected to the U.S. House of Representatives in 1976.
“Washington is full of politicians,” he said. “If you send another one down there, you’ll get the same result.”
But the WBUR and WHDH polls suggest only marginal utility in the message.
Twenty-two percent of respondents to the WBUR poll say Markey's long service in the House make them "more likely" to vote for him, 29 percent say "less likely," and 47 percent say it "makes no difference."
The WHDH survey tests out a Gomez line — that Markey is a "poster boy for term limits" — and doesn't find much traction. Twenty-eight percent of voters agree with the statement, 43 percent disagree, and 27 percent are undecided.
The WHDH poll suggests Markey's opening salvo — criticizing Gomez's refusal to sign the "People's Pledge," limiting outside spending in the race — could resonate. Seventy-one percent of voters say the pledge is "very important" or "somewhat important."
But if the critique is designed, in part, to link Gomez with the sort of conservative groups that might provide third-party funding, Markey has a ways to go. The survey found just 29 percent of voters believe Gomez is "too conservative" to represent Massachusetts.
Asked in the WBUR poll if Gomez's positions on important issues are similar to, or different from, the national Republican Party, more than 4 in 10 voters say they don't know or refuse to answer the question. The rest split into roughly even camps.
Markey's financial edge will give him an opportunity to hammer the Gomez-as-conservative message as the campaign unfolds.
When it comes to registered voters, Democrats hold a 3 to 1 edge on Republicans in Massachusetts. So any GOP candidate for statewide office has to build a big margin among independents to pull off a victory.
In the 2010 U.S. Senate special election, Republican Scott Brown won independents 65 to 34 percent en route to his upset victory over Democrat Martha Coakley, according to a post-election poll commissioned by The Washington Post.
The WBUR survey shows Gomez with a 38 to 35 percent lead among independents — a margin "much too small," Koczela says, to pull off an upset.
The PPP survey gave Gomez a much larger lead among independents: 16 points. But that's still not enough, says Koczela.
Markey has his own weakness, though. It appears that Democrats who voted for the more conservative U.S. Rep. Stephen Lynch in the party primary last week haven't fully closed ranks behind the nominee.
Markey's edge among Democrats is 63 to 14 percent. It expands to 71 to 15 percent — with 12 percent saying they "don't know" or are "undecided" — if leaners are included.
But "even that is not where he wants it to be," Koczela says. "If he could win all the 'don't-knows' and get it up into the 80s, that would be good for him. But if it stays down in the high-60s, low-70s or even mid-70s, that's a problem."
Markey's challenge with voters in his own party separates him from Elizabeth Warren, who won 89 percent of Democrats last fall when she ousted Brown from the Bay State's other U.S. Senate seat.
The Gender Gap
Gender is an important fault line in elections, too. Coakley edged Brown by just 3 percent among women voters in 2010 and lost. Two years later, Democrat Warren won women by 18 percent and cruised to an eight-point victory over Brown.
Markey, it appears, is in Warren territory for now.
He has a 15-point lead among women — 45 to 30 percent — in the WBUR poll. And the lead expands to 17 points if leaners are included.
Gomez, meanwhile, has a four-point edge over Markey among men — 40 to 36 percent. And the lead shrinks to three points with leaners.
That's well short of the 14-point margin Brown built among men in the 2010 special election.
Democrats have traditionally racked up big margins among minority voters. And here, Markey's lead is substantial, too. He's got a 61 to 9 percent lead over Gomez among non-white voters. The lead expands to 69 to 15 percent when leaners are included.
The challenge, for Markey, will be getting minority voters to the polls in large numbers.
Brown's upset victory in 2010 was not just about shrinking the gender gap and winning independents by a wide margin. It was also about geography.
His map included the South Shore, large swaths of Cape Cod, big chunks of Essex and Middlesex counties in the northeast part of the state, the Worcester suburbs in the middle of the state and the Springfield suburbs in the southwest corner of the state.
Gomez may have to put together something similar if he is to defeat Markey.
The WBUR poll breaks voters down into four regions — Boston and the inner suburbs, the outer Boston suburbs, southeast Massachusetts and central and western Massachusetts.
Those designations make for a less-than-perfect comparison to the Brown-Coakley contest. The central and western Massachusetts region, for instance, includes areas that went strongly for both Brown and Coakley.
But results from the WBUR poll suggest Gomez doesn't yet have the support Brown cultivated in two key areas of the state: Boston's outer suburbs, bending around the city from north to west to south, and the southeastern part of the state.
Markey has a 41 to 40 percent edge in the outer suburbs. And Gomez has only a one-point lead in southeast Massachusetts — 35 to 34 percent. The race is a tie in that area — 43 percent each — when leaners are included.
Gomez has an impressive 47 to 28 percent lead in central and western Massachusetts (51 to 31 percent with leaners). Markey has a lopsided 59 to 20 percent lead (68 to 22 percent with leaners) in Boston and the inner suburbs — a region that includes his congressional district.
The WBUR poll of 497 likely voters, conducted May 5-6, has a margin of error of 4.4 percent.
This program aired on May 9, 2013. The audio for this program is not available.