“What makes you different from him? Why should I vote for you and not him?”

It is the question many Democrats seem to be asking as they size up Boston City Councilor Ayanna Pressley’s primary challenge to Representative Michael Capuano.

Editor’s note: Representative Michael Capuano has conceded to Ayanna Pressley in the Sept. 4 Democratic primary. Click here for more .

Lynne Katz was posing the query on this particular day to Pressley, after hearing her speak at the Dorchester skilled-nursing facility where she lives, several weeks after Capuano delivered his own talk there.

Pressley smiled and gave a long answer to Katz’s question. But several hours later, she was still replaying the moment when she spoke to a dozen young staff members and volunteers at her spartan headquarters in a Jamaica Plain strip mall.


“We get this question everywhere, and we’re six months in,” she told her staff. “I have to say that it reminds me of when I ran for office for the first time, and the hardest question to answer was, ‘Why are you running?’ It seems that should be the easiest, but when it is so obvious to you, it can be the hardest thing to articulate.”

Both candidates are realizing that one of the biggest challenges they face is also one of the most elemental: How do they distinguish themselves from one another when they agree on most issues?

At one level, there are obvious differences: Pressley, 44, tells voters she would bring a unique viewpoint to Congress, as the first African-American woman elected to the Boston City Council and as a survivor of sexual assault whose father struggled with drug addiction and was incarcerated.

Capuano, who is 66 and white, says he is running based on his record in Congress. The former Somerville mayor was first elected to Capitol Hill in 1998 — the last time he faced a difficult race. He and his supporters emphasize the value of having seniority in the House.


On policy, however, the disagreements can be harder to parse.

Pressley draws perhaps her sharpest contrast with Capuano when she points to her recent support for the movement to abolish Immigration and Customs Enforcement; Capuano says changing immigration policies is more important. She also tells voters that she does not accept money from corporate political action committees while her opponent does.

But she says distilling other areas where she and Capuano disagree can be difficult.

“Look, I know this is hard because brevity is not my strong suit,” Pressley told her staff. “I don’t have some elevator pitch, and I should figure that out.”

Capuano says he doesn’t attempt to explain the differences between him and Pressley to voters, and only is asked that question by the media.

“I won’t ask people to vote for me on the basis of what I did yesterday,” Capuano said. “But what I did yesterday should inform you as to what I’m likely to be able to do tomorrow, particularly if Democrats take the House back. I’m a very effective advocate not because I say so, but because I’ve actually done it and I can prove it, and I can show you things I’ve done all the way from Randolph to Everett and everywhere in between.”

Pressley downplays Capuano’s record, saying taking progressive votes “is not a profile in courage” in one of the most liberal districts in the country.


She says she hopes to serve in the mold of two rising Democratic Party stars, Representatives Katherine Clark and Joseph P. Kennedy III, who have built national followings despite being in the minority and lacking seniority.

“It is about voting the right way, but that’s not enough,” Pressley told Katz, the voter who asked about the differences between her and Capuano. “This district — and these times — require a leader that will vote the right way and will lead and legislate, and I’m proven in that regard.”

She mentioned her record in pushing for more liquor licenses for restaurants in Dorchester, Roxbury, and Mattapan; crafting a policy to help pregnant and parenting teens graduate from high school; and advocating on behalf of victims of gun violence.

After the event, Katz said she was impressed by Pressley but still undecided.

“We do need new people in there,” she said. “But I like Mike Capuano so I’m going to have to do some heavy thinking.”

At a bull session at her campaign office, Pressley urged her staff to “distill one example of contrast that is meaningful for you” to give to voters, and listed several she sees as significant.

She said, for instance, that although she and Capuano both support tougher gun laws to prevent school shootings, she would go further by pushing for more school social workers and counselors. She also accused Capuano of supporting “the militarization of schools.”


On abortion rights, she says, she would go further than Capuano by working to repeal the Hyde Amendment, which prohibits federal funding of most abortions.

And she said she would be a more effective advocate for immigrants by pushing for in-state tuition rates for undocumented students at public colleges and universities.

To crystallize the point, Wilnelia Rivera, Pressley’s political consultant, said: “The overarching message is the difference between a reliable vote and a champion.”

In an interview, Capuano expressed puzzlement at the argument.

On the Hyde Amendment, Capuano said he is an ardent opponent of that law, which congressional abortion rights supporters have been trying to repeal for decades. Capuano’s campaign made Representative Rosa DeLauro, a Connecticut Democrat and staunch women’s rights advocate, available to vouch for Capuano on the issue. She called him a “stalwart supporter” of abortion rights who vigorously opposes the Hyde Amendment.

As for Pressley’s argument that she will fight for in-state tuition for undocumented students, Capuano said, “She is running for the wrong office. That is done in the state Legislature.”

He also scoffed at the notion that he supports “the militarization of schools.”

The accusation is based on an interview Capuano gave after the Parkland, Fla., shooting in which he recalled that, as mayor of Somerville, he placed a police officer in a school that was having problems and that officer “worked with the kids and there was no violence in the schools after that happened.”

“I don’t consider that militarization at all, but if others do, so be it,” Capuano said.


He also pointed to several achievements to argue that he’s more than a reliably liberal vote.

He cited millions in federal funding he helped secure for community health centers, famine relief in Sudan, the Whittier Street public housing development in Roxbury, and the Fairmount commuter rail line through Dorchester, Mattapan, and Hyde Park.

“None of that was done by a vote,” he said. “That was done by advocacy, and on and on and on throughout the years I’ve been here. It’s exactly what I do, and sometimes I do it in front of the media and sometimes I don’t.”

Michael Levenson can be reached at mlevenson@globe.com. Follow him on Twitter @mlevenson.