The Ward 5 Democratic Committee voted on Tuesday to formally reprimand At-Large City Councillor Michelle Wu for her controversial vote for South Boston Councillor Bill Linehan as Council president. After a heated debate and a defense from Wu, the left-leaning Democratic Committee’s members voted 18 to 11 to send Wu a letter voicing their disappointment and disapproval.

Committee Chairman Ross Levanto called the letter “a pretty extraordinary action by a committee, but not without precedent.” The committee previously sent a letter of disapproval to US Rep. Stephen Lynch after his vote against President Obama’s health care bill in 2010.

Ward 5 includes portions of the Back Bay, Beacon Hill, the South End, the Fenway, and Chinatown. The Tuesday night meeting was held at the Community Church of Boston in the Back Bay.

Speaking in favor of the reprimand was former Rep. Paul Demakis, who used his own experience as a lawmaker to explain how a legislative leader can shape the debate and values of a body.

“These decisions matter,” Demakis said. “Who you vote to put in charge of a body matter. They control committee assignments, they control the flow of legislation, they decide what happens. It matters.”

At one point during the debate, the group began arguing loudly, with at least one member demanding that Levanto remove an out-of-order debater from the room.

In a shaky voice, the apparently ailing Wu apologized for disappointing the ward’s progressives, who see Linehan as a conservative obstacle to their agenda. She explained that her vote was based on conversations she had with Linehan and the other two councillors who expressed interest in the position, Matt O’Malley and Tito Jackson. After researching the role of the City Council president, Wu said she decided it is a mostly administrative position and so she based her support for Linehan on his promises to decentralize power and staffing in the council.

“So I decided I would cast my vote, my very first vote on the council, on ideas,” Wu said.

Wu conceded that she didn’t foresee the symbolic nature of voting for a figure as unpopular with progressives as Linehan and the backlash it has caused. As for the letter, Wu said she appreciates her constituents using a formal communication to register their disapproval. She said she will continue to vote based on her values and her own examination of the issues regardless of the political result.

“That may not bode well for me for 2015, but that’s the kind of elected official I want to be,” she said. She added that Ward 5 has always felt more like a family than a political grouping and said that she’s “very familiar with contentious family discussions.”

Committee member Sarah Wenig expressed her opposition to the idea that the formal letter was necessary to convey feedback to Wu. “If you felt that strongly about Michelle’s vote, you just say something to Michelle,” Wenig said.

Executive Board member Fran Burke explained that the committee’s leadership wished to address all the talk and controversy surrounding Wu’s vote for Linehan and to hold her accountable should the full committee choose to send the letter.

“If they decided to send it, we wanted something that showed our disappointment, but that showed the value of our City Council election. We wanted to move forward,” Burke said.

Committee member Josh Zakim, Wu’s colleague on the City Council, chose not to vote on the letter to Wu. He told the Reporter his vote for At-Large Councillor Ayanna Pressley for the president’s post speaks for itself. Pressley lost to Linehan on an 8 to 5 vote in January.