Democratic Party activists who tried unsuccessfully to sink Hillary Clinton’s nomination at last year’s convention are at it again, pestering national party members ahead of next week’s vote on a new chairman.

Party leaders are eager to incorporate the energy of progressives who buoyed Sen. Bernard Sanders’ presidential campaign last year — but less enthusiastic about the activists’ rough edges that continue to irk many Democratic National Committee members.

They say the phone calls to lobby for Rep. Keith Ellison, the choice of progressives, over Tom Perez, viewed as the establishment choice, are out of control.

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“It was over the top, and I contacted Keith, and Keith tried to stop it, to his credit. It took a while,” said Marcel L. Groen, chairman of the Pennsylvania Democrats. “I want their enthusiasm and energy, but I do want it harnessed. I am not interested in anarchy.”

Mr. Groen said he is a fan of both Mr. Ellison and Mr. Perez, the Obama administration’s former labor secretary — but the pro-Ellison effort convinced him to go public with his support for Mr. Perez.

“Let’s say you were completely uncommitted,” he said. “You don’t want 300 people calling you and telling you what to do.”

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While there are other candidates in the race for the DNC chairmanship, it appears to be a two-man affair between Mr. Perez and Mr. Ellison.

Mr. Perez claimed this week to have the support of 180 DNC members, which would put him 44 shy of the magic number of 224 needed to win.

Mr. Ellison, however, pushed back on Thursday, suggesting in an email blast that the claim was bogus and that Mr. Perez was trying to trick the world into thinking the race was over with nine days to go before 447 members cast their votes in Atlanta.

The Perez camp stood by its tally.

It’s no surprise that the chairman’s race has turned intense, particularly after it emerged that the previous chairwoman, Rep. Debbie Wasserman Schultz, used her position to try to dent Mr. Sanders’ presidential bid last year.

Enraged at those tactics, Sanders supporters heatedly lobbied the party’s bigwigs, the superdelegates, and then staged protests that marred Mrs. Clinton’s nominating convention.

Now many of the same progressives are backing Mr. Ellison in the chairman’s race, including #Bernie2020, and they’ve circulated the names, email addresses and phone numbers of DNC members, and urged activists to tell them to elect Mr. Ellison.

David O’Brien, an undecided DNC member from Massachusetts, said he has been on the receiving end of pro-Ellison emails and phone calls, and said they have picked up speed ahead of the Feb. 25 vote.

Mr. O’Brien said he is torn between Mr. Perez and Mr. Ellison, and shared a recent conversation in which an Ellison backer told him it would be an “injustice” if the Minnesota congressman does not get the job.

“I don’t think a person has approached me who was a super pro-Hillary person who said you would have to vote for Tom,” Mr. O’Brien said. “On the flip side, a whole lot of people have approached me who said Bernie was wronged; Keith was abused in the press. Help us out here.”

Mr. O’Brien said Mr. Ellison has a great platform and his supporters would be better off focusing on that rather than dwelling on the past.

He said members of the DNC are just as upset with Mrs. Wasserman Schultz, who resigned over hacked emails, released by WikiLeaks, that suggested the DNC was in the tank for Mrs. Clinton.

“Debbie was wrong, and Debbie deserved to go, but don’t get mad at anybody with a DNC title next to them,” he said. “I felt wronged too.”

The passion for Mr. Ellison was on display at a recent DNC forum in Baltimore, where his backers had the loudest presence and also jeered Mr. Perez — to the dismay of some members.

“The heckling and all that has been going on since the convention, since the campaign, that is old,” said Yvette Lewis, a DNC member from Maryland who pledged her support for Mr. Perez following the event. “I don’t know if it hurts or helps anyone, I just know that is needs to stop.”

For his part, Mr. Ellison has preached party unity, and has touted his friendship with Mr. Perez.

He also has tried to keep a lid on his supporters.

“Reminder: please leave direct contact with DNC Members to Keith. Thank you!” he said on Twitter this week.

The message, though, didn’t stop pro-Ellison activists from crashing a forum Wednesday at the Woman’s National Democratic Club in Washington.

They interrupted Mr. Perez midsentence and demanded that he commit to going after Democrats who cooperate with President Trump and unfurled a banner that read: DEMS: #RESIST TRUMP OR BE REPLACED.”

Following the event, Mr. Ellison turned to Twitter once again after an activist-journalist blasted out photographs of the congressman “breaking bread” with Mr. Perez at a restaurant under the banner “Breaking News.”

“We’re friends,” Mr. Ellison responded on Twitter. “It’s OK.”