In 1981, Tim Walz and his father traveled to the nearest Army National Guard enlistment officer to his hometown in Nebraska.

“We met up with a lieutenant who had to get off his tractor from early spring plowing,” Walz said in a 2018 interview with MPR News. “And we did the oath of enlistment right there on the edge of a field with the recruiter. And that led me on a 24-year journey.”

The Minnesota governor, and now running mate with Vice President Kamala Harris, has often talked about his service in the National Guard. Now others are talking about it too, and not always in glowing terms, especially when it comes to Walz’s stepping away from the Guard.

Harris called him a “patriot” in Philadelphia on Tuesday, the first rally the two held together.

“To his fellow veterans. He is Sergeant Major Walz,” Harris said, as the crowd cheered.

Republican vice presidential candidate Sen. JD Vance took aim at the governor’s accounts of his service on the campaign trail, calling Walz’s decision to leave the National Guard when he did “shameful.”

Members of the National Guard train to fight in wars, and to respond to national security threats. They also are called up for state emergencies.

Walz served in Nebraska, Texas and Arkansas before moving to Minnesota in 1996. He was in the 1st Battalion, 125th Field Artillery based in New Ulm.

He specialized in heavy artillery and had ribbons for proficiency in sharpshooting and hand grenades, according to military records MPR News obtained through an open records request.

During his service, he suffered hearing damage due to heavy artillery use. He later had surgery to address that.

His training missions included one near the Arctic Circle in northern Norway.

In 2003 he was deployed to Italy for nine months, providing support for the war in Afghanistan.

“[Our] responsibility was to provide support at these bases in the early parts of the war in 2003, where these troops in the active force went forward into the war zone,” Walz said. “And we went in and provided base security, provided training on the backside, because the regular force was deployed downrange.”

On May 15, 2005, Walz retired from the Guard. His separation record says he did so honorably.

Later that year, his battalion was deployed for the Iraq war.

The 1-125th Field Artillery “received an alert order for mobilization to Iraq on July 14, 2005. The official Department of the Army mobilization order was received on Aug. 14, 2005, and the unit mobilized on Oct. 12, 2005,” said Lt. Col. Ryan Rossman, Minnesota National Guard’s director of operations.

At the time of his retirement, Walz was 41 and wanted to run for Congress. He was elected to the First District Congressional seat the following year.

In the 2022 race for governor, Republican candidate Scott Jensen — flanked by veterans — pointedly questioned Walz’s decision to leave the Guard before the battalion’s Iraq deployment.

“In my eyes, today is the day that Tim Walz is indicted for lack of leadership and an unwillingness to do his duty, and Minnesota needs to know about it,” Jensen said.

Walz said in 2018 he believed he could make a difference as a voice for soldiers in Congress.

“I wouldn’t put myself as a hero, but 24 years of service commendations, rising to a rank that your listeners who are in the military know, you don’t get to bluff your way to that, you earn that and, and I’m certainly proud of that,” he said.

Allan Bonnifield served with Walz, whom he first met in 1999. In a 2018 interview with MPR News, Bonnifield said Walz debated whether he should focus on a run for Congress or stay in the National Guard.

“He weighed that decision to run for Congress very, very heavy,” Bonnifield said. “He loved the military, he loved the Guard, he loved the soldiers that he worked with, and making that decision was very tough for him. Especially knowing that we were going on another deployment to Iraq. He didn’t take that decision lightly at all.”

Vance, who criticized Walz’s record, served four years in the Marines. He was deployed to Iraq for six months in 2005 as a combat correspondent, or military journalist according to Task and Purpose, a publication that covers the military.

Bonnifield said Walz focused on veterans in Congress. Of the 85 bills Walz sponsored over his six terms, nearly half had to do with veterans’ issues.

“He worked on making it easier for Guard members struggling to get help and contact the right people for post traumatic stress help, for the suicidal thoughts, for just making things quicker and making it so people realized it is an actual problem, it’s not something that will just go away,” Bonnifield said.

There have also been questions raised by critics about two aspects of Walz’s retirement documents. First, his title at retirement, and second, a lack of a signature on his separation record.

Walz left the military at the rank of command sergeant major, one of the top for an enlisted soldier.

Personnel file records show that he was reduced in rank months after retiring, leaving him as a master sergeant for benefits purposes.

“[Walz] held multiple positions within field artillery such as firing battery chief, operations sergeant, first sergeant and culminated his career serving as the command sergeant major for the battalion,” said Lt. Col. Kristen Augé, a public affairs officer with the Minnesota National Guard. “He retired as a master sergeant in 2005 for benefit purposes because he did not complete additional coursework at the U.S. Army Sergeants Major Academy.”

In the separation record for Walz, a signature box says “Soldier not available for signature.” The guard said that’s relatively routine for these documents.

“For members of the reserve components, who are not available for signature, using the regulatory statement of ‘not available to sign’ is common,” said Army Col. Ryan Cochran, the Minnesota National Guard’s director of manpower and personnel. “This statement is authorized and directed by both Army Regulations and National Guard Regulations to ensure the timely processing of administrative actions.”

MPR News politics editor Brian Bakst and former APM Reports correspondent Chris Haxel contributed reporting to this story.