AS A MARINE platoon leader in Iraq, Seth Moulton understood the discipline of the military chain of command as well as anyone. As a congressman with a healthy mix of ambition and an independent streak as wide as an eight-lane highway, he has become a master of disruption, exercising with abandon the free rein that comes with civilian life in elected office. 

Moulton had the temerity to challenge a fellow Democrat on his way to winning a hard-fought primary, and he then bucked the code of party loyalty and respect for seniority by saying Nancy Pelosi wasn’t the right one to lead House Democrats. 

Now the latest Moulton moment: A secret trip on Tuesday that the Salem pol took to Afghanistan with Republican congressman — and fellow Iraq war veteran — Peter Meijer of Michigan. The congressmen, who were on the ground at the Kabul airport for less than 24 hours, say they wanted to see first-hand the effort to get American citizens and Afghans who worked with the American military out of the country now that it has fallen to the Taliban. 

Moulton has been sharply critical of the Biden administration’s handling of the Afghanistan pull-out. “To say that today is anything short of a disaster would be dishonest,” Moulton said in a statement released August 15, the day Kabul fell. “Worse, it was avoidable.” When President Biden said some of the chaos was caused by Afghan citizens who had not wanted to leave earlier, Moulton called the explanation “utter BS.” 

The congressmen’s quick visit was not approved as part of standard congressional fact-finding travel, the Washington Post reported, and it prompted scathing rebukes from Pentagon and administration officials. 

“It’s as moronic as it is selfish,” an unnamed administration official told the Post

“It’s one of the most irresponsible things I’ve heard a lawmaker do,” a diplomat not authorized to speak publicly about the trip told the paper. 

Despite the suggestion that the lawmakers might have taken seats away from those desperately trying to leave the country, a spokesman for Moulton said the congressmen had vowed to only leave Kabul on a plane with empty seats and wound up sitting in empty seats reserved for crew members. 

Pelosi sent a letter on Tuesday to House members that did not explicitly mention the congressmen’s trip. “I write to reiterate that the Departments of Defense and State have requested that Members not travel to Afghanistan and the region during this time of danger,” she wrote.

On Monday, Globe columnist Joan Vennochi said that Moulton has been raising questions for months about US plans for getting citizens and Afghan allies out of the country and has rightly called out the intelligence failures that have now come into full view. 

“Moulton started talking about that truth right away. Painful as it is, more Democrats need to join in the conversation,” she wrote

“As Members of Congress, we have a duty to provide oversight on the executive branch,” Moulton and Meijer said in a joint statement about their trip. “We conducted this visit in secret, speaking about it only after our departure, to minimize the risk and disruption to the people on the ground, and because we were there to gather information, not to grandstand.”

The statement sought to counter a charge that has been leveled at Moulton by detractors ever since his winning campaign in 2014. 

“Moulton will have to navigate the thin line between courage and opportunism,” Vennochi wrote four years ago, framing the challenge that seems to continue to define his public profile.