WASHINGTON — Seth Moulton's opposition to another ground war in Iraq is rooted in firsthand experience acquired from four tours. As a young Marine, he saw how quickly a militant threat could transform U.S. military advisers into a force entangled in the months-long battle for control of Najaf, some 100 miles south of Baghdad.
These are not simply the doubts of a former platoon leader three years after combat forces left. Moulton is challenging nine-term Democratic Rep. John Tierney in Tuesday's bitter, crowded Massachusetts primary. His military service has drawn attention to his first-time candidacy and made him a formidable foe to Tierney.
"Americans have to realize that when the president says he's sending military advisers to Iraq, make no mistake, these are U.S. special forces or Marines or Rangers or other units that are American ground troops," Moulton said in an interview. It was true in Vietnam, he points out. It was true of Iraq.
Moulton's reservations reflect a war-weary nation's skepticism about the next U.S. steps to fulfill President Barack Obama's vow to destroy Islamic State militants and rising fear about mission creep as American forces in Iraq now exceed 1,000.
The race in the northeast corner of Massachusetts stands as one of the few where an incumbent House Democrat is fighting off members of his own party. In June, New York Democrats gave Rep. Charlie Rangel a clear shot at a 23rd term in his primary. In California, seven-term Rep. Mike Honda is in a tough race with fellow Democrat Ro Khanna after they finished one-two in the state's jungle primary.
Democrats will hold those two seats, but Massachusetts' 6th Congressional District is up for grabs in November's general election. The GOP is upbeat about the prospects for Richard Tisei, a former state senator and openly gay Republican who nearly knocked out Tierney in 2012, losing by just 4,330 votes.
Tierney is a political survivor who won re-election despite a gambling scandal involving family members, including his wife. The Democratic stalwart who has focused on education and jobs during his 17 years in the House proudly boasts of his office's constituent service. He argues that experience is what matters to voters even as Democrats are expected to remain in the minority in the House.
"They can have a backbencher who's just trying to get their feet on the ground, especially here in the minority, or you can have somebody who's been there, who's respected by people on both sides," the 62-year-old Tierney said of Moulton in an interview.
Tierney is facing four Democratic rivals in the primary, including the 35-year-old Moulton.
The Harvard graduate who enlisted in the Marines in 2001 was first on the air with a campaign ad in which he tells voters, "I'm a progressive Democrat who opposed the war in Iraq. But I also was a Marine serving my country. So I went, led my platoon and always ate last after my men."
Moulton, who backs abortion and gay rights, tighter restrictions on gun ownership and comprehensive immigration reform, calls himself a "Democrat for real change."
That commercial and another criticizing Tierney as a career politician ran at a cost of $468,000. VoteVets, a group dedicated to electing veterans to Congress, invested even more — $511,000 — to run ads in which World War II veteran Joel Mitchell says he supports Moulton, "a Marine from Marblehead," who will always have his gratitude. Marblehead is a coastal town in Massachusetts.
Some 8 percent of the district's population served in the military and about 15 percent are age 64 and over.
"Seth Moulton is the future in Massachusetts 6," said Jon Stoltz, chairman of the VoteVets. "It's just a matter of time, and whether or not time is next week; it probably is."
Stoltz said the VoteVets ad would be updated to include endorsements for Moulton from both The Boston Globe and The Boston Herald.
Moulton has been on the screen before, uttering the final words in the 2007 documentary "No End in Sight," a critical look at the war in Iraq and U.S. involvement.
In the final frames, Moulton says, "You're telling me that this is the best America can do? No way. Don't tell me that. That makes me angry."
Tierney, who voted against authorizing the use of military force in Iraq in October 2002, wants Obama to spell out the scope of the mission now and seek a congressional vote on additional use of force.
In response to Moulton, Tierney answered this week with a campaign ad linking him to Republicans who support gun rights and oppose abortion rights. The ad focuses on money the Moulton campaign received from the White Mountain PAC, which is affiliated with former Sen. Judd Gregg, R-N.H.
"Moulton took money from a special interest group that only funds Republicans," a narrator says in the ad.
The Moulton campaign said the $1,000 was returned earlier this year and the ad was a sign of Tierney's vulnerability in the primary.
Tierney also is airing a positive ad that's part personal story, part congressional work to make education more affordable. The commercial says Tierney has "never forgotten who he's fighting for."
Tierney said in an interview he followed the advice of the late Massachusetts Sen. Ted Kennedy, who said "run like you're in last place even if you're unopposed."