More than 8.7 million Americans served in the U.S. military during the Vietnam War, and more than 3.4 million of them deployed to Southeast Asia in support of it, according to the Department of Veterans Affairs. In a long, bloody conflict marked by jungle warfare and political turmoil, that means large numbers of Americans are still grappling internally with the legacy of the war.

The Defense Department, following a lawsuit this year by Vietnam combat veterans, moved Wednesday to help in a new way. Pentagon leaders said they have issued guidance to military officials who consider petitions for discharge upgrades that potentially pave the way for thousands of veterans coping with post-traumatic stress disorder getting their other-than-honorable discharges upgraded. There are several categories of “bad-paper” discharges, including “dishonorable” and “bad-conduct.”

Veterans today can be given a medical discharge while coping with PTSD, clearing a path for them to receive medical benefits from the VA. But the condition wasn’t recognized until 1980, potentially leaving thousands of Vietnam War veterans out in the process.

“This is our responsibility and the right thing to do for veterans,” said Defense Secretary Chuck Hagel, a former Army infantryman who was wounded by a mine in a Vietnamese jungle in 1968. “This new guidance reflects our commitment to those who served our country during times of war many decades ago.”

The decision follows a lawsuit filed in March by five Vietnam veterans and three veterans’ organizations: Vietnam Veterans of America, Vietnam Veterans of America Connecticut State Council, and the National Veterans Council for Legal Redress. With representation from Yale Law School’s Veterans Legal Services Clinic, they alleged that the military had systematically avoided dealing with petitions for discharge upgrades despite evidence of post-traumatic stress in some applicants.

Hagel said in March that he was personally looking into the case. His move this week had not been forecast, but it was greeted with cheers by at least one veterans’ group.

“This decision will not be a blanket approval for every upgrade request, but it does open an avenue for those veterans who may have been diagnosed with PTSD years after separation to submit new evidence and hopefully correct an injustice from the past,” said John W. Stroud, the national commander of the Veterans of Foreign Wars of the United States organization.

The Pentagon will now likely face scrutiny over how quickly petitions are processed, and what it will do for those affected. The lawsuit said 250,000 Vietnam-era veterans received other-than-honorable discharges, and that 80,000 of them could have post-traumatic stress.

The review boards should give “liberal consideration” to petitions citing post-traumatic stress, according to documents the Pentagon released Wednesday. Special consideration will be given to veterans who are diagnosed by the VA with PTSD or PTSD-related conditions, the documents said, but it left open the possibility of securing a discharge upgrade without it.

But not everyone who applies will get an upgrade. The Pentagon said the review boards should “exercise caution in weighing evidence of mitigation in cases in which serious misconduct precipitated a discharge with a characterization of service under other than honorable conditions.”

The story of one of the veterans who sued is emblematic of what the Pentagon will review. Conley Monk, a Marine veteran, has said he was struggling with nightmares and drugs when his commanders said he could accept a bad-paper discharge or be imprisoned in a military brig in Okinawa, Japan. He chose to go home, but told the Connecticut Mirror in March that he still wakes up in a cold sweat every night, and takes two T-shirts to bed.

“When I was in high school, I worked at the VA hospital in the kitchen as a dishwasher. But after I came home from Vietnam, I couldn’t even get my job back as a dishwasher because of my bad paper,” Monk told the Associated Press in March. “My discharge status has been a lifetime scar. If I were discharged today, my PTSD would be recognized and treated and I wouldn’t be punished for having a service-connected medical condition.”