With U.S. troops now serving in more than 140 locations worldwide, the skills and experiences immigrants bring to the military have become all the more vital to national security. Today, soldiers are often asked to not only take and hold terrain, but also to bring together tribes and factions who share difficult ethnic and religious histories.

America’s quest to overcome its complex divisions remains incomplete. But where the country has succeeded it is often reflected in the ranks of the armed forces—in the men and women of many different beliefs, races, and backgrounds serving together to accomplish a common mission. Their ability to overcome the burdens of history is part of the power of America’s example and its promise to the world.

And yet, according to reporting by The Washington Post, the Trump administration is now considering breaking an Obama-era promise to military recruits who lack legal immigration status: that if they serve in uniform for the United States, they can become citizens in return. There are now 1,000 of these men and women, whose entry into the armed forces was being fast-tracked because of high demand for their linguistic and medical skills, and who now risk deportation.

In addition to potentially reneging on commitments to these recruits, the administration may enhance security screening for more than 4,000 other troops, the majority of whom are naturalized citizens. Part of the logic behind these changes is an argument that the previous administration was too lax in accepting immigrant recruits, though the Pentagon has raised flags concerning the prudence and lawfulness of subjecting a certain set of soldiers, many already citizens, to a more invasive security review.

For a military that has been at the vanguard of some of the nation’s most important transformations—desegregating more than a decade before the Civil Rights Act became law, and providing equal pay for men and women in the same roles more than 40 years ago—such measures would represent a dramatic step backward. They are not, however, completely unexpected given the record of this young presidency.

It was from the Pentagon during his first week in office that Trump made clear he intended to translate the caustic, anti-immigrant rhetoric he used on the campaign trail into U.S. policy. On January 27, on a stage at the Pentagon’s Hall of Heroes, Trump signed his executive order blocking refugee admission and severely restricting immigration from seven Muslim-majority nations.

Signing such a directive in a room honoring more than 3,500 Medal of Honor awardees, a full 20 percent of them born on foreign shores, was an odd choice. But as Trump considers how his immigration policies affect the nation’s security, and particularly the strength and readiness of the military, it would be wise for him to reflect on the names engraved on the Hall of Heroes walls, Americans who have earned the U.S. military’s highest honor. Some 700 of them were first-generation immigrants and hundreds more the children of immigrants.