MANCHESTER, N.H. — A state representative and former head of the New Hampshire AFL-CIO says he’s seeking the Democratic nomination for the state’s 1st Congressional District in 2018.

Mark MacKenzie, of Manchester, joined the local fire department in 1974 and retired after 25 years. He was state AFL-CIO president for 25 years and is serving his first term in the House.

He said the American dream has dissolved into “the American struggle,” and that working families deserve an economy that works for them.

He’s joining at least three other Democrats to succeed Democratic Rep. Carol Shea-Porter, who is stepping down after her term ends. Former Somersworth mayor Lincoln Soldati, Rochester City Attorney Terence O’Rourke, and former Marine Maura Sullivan are running.

Among Republicans, state Sen. Andy Sanborn of Bedford and former Liquor Commission Chief of Enforcement Eddie Edwards have launched campaigns.