In Afghanistan in 2007, an immigrant and fellow U.S. soldier, who I was helping obtain his U.S. citizenship, mentioned to me that his wife was having trouble getting their child to the doctor. They were married right before we deployed, and she hadn’t obtained the dependent military identification card that would allow her access to our stateside post and the doctors who provided the health benefits to which his son was entitled.

“Sergeant Smith,” he told me, “she doesn’t have an ID card.”

And, he went on, she couldn’t get one. I started to explain a few different ways that his wife could get an identification card without him being physically present in the United States to sponsor her, but after a perplexing back-and-forth I realized what the issue was: His wife was an undocumented immigrant.

This soldier had found his way to the United States from Central America, joined the military after gaining legal permanent resident status — his “green card” — volunteered for the airborne infantry in a time of war, and left his undocumented spouse and newborn child in uncertainty on combat orders that placed his life at risk, all so they could become Americans faster. This month, the military has announced that it is going to make that process harder. It’s a slap in the face to immigrants who serve.

When I served with the 82nd Airborne Division in Afghanistan, I took on the duty of helping brave immigrants apply for and expedite their citizenship process, literally creating new Americans while in the combat theater. Troops who submitted paperwork early on in our deployment left home as green-card holders and returned home as full-fledged citizens, often taking the oath of citizenship in the combat zone, in uniform, with rifles slung across their backs. Of everything I did during my service, there is nothing I’m prouder of than this.

Think about it: Men and women who aren’t yet U.S. citizens volunteer to sacrifice on behalf of the vast majority of us who never put on the uniform. Recognizing these immigrants’ service by clearing the path toward citizenship is simply the right thing to do.

And until a couple of weeks ago, green-card holders in the military were eligible for certification of their honorable service, for the purposes of having the citizenship process expedited, after “one day of service.” But two weeks ago, the Defense Department announced that active-duty troops would have to wait at least six months — a full year for reservists — before getting certified. That’s on top of a new requirement that green-card holders have their background investigation completed and receive their military security suitability determination “prior to entry in the active, reserve, or guard service”; before, they could ship out to basic training while their background check was still in progress. And as The Washington Post’s Alex Horton reported last week, what the Defense Department didn’t announce is that the Army — the service branch in which I proudly served — has a new policy that “halts indefinitely all enlistments involving green-card holders seeking to join the Army Reserve and National Guard.”

The military’s stated concern is about security — not something to take lightly. But it’s a sweeping policy that comes in response to relatively few reported cases of immigration fraud involving service members or recruits.

The net effect is that immigrants will wind up being discouraged or potentially, in some cases, prevented from serving in our armed forces, to the detriment of our military.

It has long been our country’s policy and practice not just to allow but to actively encourage non-citizens to serve in our armed forces. Leaders in the earliest days of the republic recognized that immigrants bring immense benefit to the military community. George Washington enlisted the expertise of Baron Friedrich von Steuben, a former Prussian military officer, to organize and train his troops at Valley Forge. Von Steuben later became inspector general of the Continental Army. According to the Center for American Progress, 18 percent of Union troops during the Civil War were immigrants. During World War I, more than 192,000 immigrants acquired citizenship through military service. As of 2012, around 5,000 green-card holders were enlisting each year.

Aspiring Americans strengthen our forces with skills that are in high demand and low supply, such as translation and cultural expertise. According to the Immigration Policy Center, in the years following 9/11, immigrants helped the military meet recruitment goals in key military occupations.

The guys whose status as Americans I helped codify were from all over the globe. One of my fellow soldiers was an infantry team leader from Sudan. Another was a logistics specialist for an infantry company engaged in some of the fiercest fighting in the combat theater; he ensured that trigger-pullers on the front line had the food, water and ammunition they needed to survive. Originally from Nigeria, he supported his extended family on a private’s salary. He initially joined the Army Reserve, and, it’s worth noting, later requested transfer to active duty during basic training. If the Army’s new green-card rules were in effect then, he might not have arrived for the first day of boot camp.

This latest policy shift falls right in line with the same shortsighted devaluing and weakening of the fortifying diversity of our armed services that we’ve seen when President Trump says he’s thinking about banning transgender troops from serving.

Since the inception of our nation, military service has been a ladder of opportunity for people from all walks of life. With these new rules, there might as well be “Aspiring Americans Need Not Apply” placards on the doors of military recruiting station. It’s a shocking contradiction of American values, and the force we trust to protect us will be weaker because of it.