One of the Legislature’s point people on veterans’ affairs threw his support behind a campaign to give service members a bigger role in Massachusetts Democratic Party conventions.

Sen. John Velis of Westfield, who co-chairs the Veterans and Federal Affairs Committee, announced Friday he is on board with a proposal from Congressman Seth Moulton to add veterans to the list of “marginalized communities” that can be named as “add-on delegates” for state Democratic party conventions.

“Less than 1% of our country’s population serves in our military today. Our state party needs to do everything we can to elevate those voices and ensure that veterans are included in our party’s platform,” Velis, himself a veteran of the U.S. Army Reserves, said. “Massachusetts veterans have selflessly and courageously served our nation and understood the importance of protecting our democracy. Their insight and experience are invaluable to the decisions our state party makes and they deserve to be represented at our conventions.”

Velis’ office said the party will take up the proposed change to its charter at its convention in Lowell on Sept. 23.

City and town Democratic caucuses select delegates to participate in each convention, and party leaders later on can add more people to the list to ensure the group is representative of the state’s demographic makeup.

At a subcommittee meeting last week, the party voted to advance a proposal from Moulton that would allow veterans to be selected in that add-on process alongside underrepresented racial and ethnic groups, people with disabilities, and LGBTQ people.

Politico reported Friday that the measure drew some criticism from progressives, including Velis’s colleague Sen. Becca Rausch of Needham, who argued that it would reduce diversity among delegates because veterans tend to be whiter and older than the state as a whole.