“I have had strong disagreements with him. I don’t think he could have been more wrong than he was in his attack on Nancy Pelosi.
“I feel his running for president is unfortunate. In Massachusetts, Elizabeth Warren has already staked that out, based on a much fuller and more impressive record.
“I think he is running the risk of being seen as always challenging women political figures.
“He is claiming that he would transform things, but I am not convinced by all this generational politics.”
Mr Moulton’s maverick nature has not surprised Jon Soltz, chairman of VoteVets, a progressive military veterans organisation which endorsed Mr Moulton’s congressional campaign.
“He is a risk taker,” he said. “To understand Seth, you have to look back to his first campaign, when he took on the Democratic party machine and won.
“In the 2014 congressional race, the Republican governor won the district, but Seth saved the seat for the Democrats.
“So he entered Congress without being beholden to the party machine.
“He is running at a time when the Democrats have had a generational shift and he has to tap into that. He did well in his CNN Town Hall where his position on guns will appeal to the party’s base.”