WASHINGTON (News Nation) — The Pentagon on Friday effectively blocked displays of the Confederate flag on military installations, in a policy that doesn’t mention the word ban or name that specific flag. The policy was laid out in a memo made publicly available on the U.S. Department of Defense website.

Signed by Defense Secretary Mark Esper on Thursday night, the memo lists the types of flags that are allowed to be displayed publicly at military installations. The Confederate flag is not among them — thus barring its display without singling it out in a “ban.”

“We must always remain focused on what unifies us, our sworn oath to the Constitution and our shared duty to defend the nation,” Esper’s memo states. “The flags we fly must accord with the military imperatives of good order and discipline, treating all our people with dignity and respect, and rejecting divisive symbols.”

Acceptable flags listed in the memo include the U.S. and state banners, flags of other allies and partners, the widely displayed POW/MIA flag and official military unit flags.

The memo applies to “public displays or depictions of flags by Service members and civilian employees in all Department of Defense work places, common access areas, and public areas, including the outside area of government-operated or public-private venture housing.

Confederate flags, monuments and military base names have become a topic of national discussion in the weeks since the death of George Floyd. Protesters decrying racism have targeted Confederate monuments in multiple cities. Some state officials are considering taking them down, but they face strong opposition in some areas.

A Defense Department official familiar with the matter spoke to the Associated Press and said the decision not to name a specific prohibited flag was to ensure the policy would be apolitical and could withstand potential legal challenges based on free speech. The official said the White House is aware of the new policy.

President Trump has rejected any notion of changing base names, and has defended the flying of the Confederate flag, saying it’s a freedom of speech issue.

According to Esper’s memo, the display of unauthorized flags — such as the Confederate banner carried during the Civil War — is acceptable in museums, historical exhibits, works of art or other educational programs.

The Marine Corps has already banned the Confederate flag. Gen. David Berger, the commandant of the Marine Corps, directed his commanders in early June to remove public displays of the Confederate battle flag. That flag, which some embrace as a symbol of heritage, “carries the power to inflame feelings of division” and can weaken the unit cohesion that combat requires, Berger said.

Military commands in South Korea and Japan quickly followed suit. The new policy does not affect or rescind those bans.

The other three military branches were all moving to enact similar bans, but they paused when Esper made it known he wanted a consistent policy across the whole department. Now they will instead issue this new policy to their troops and employees.

Defense leaders have been debating the issue of banning the Confederate flag for weeks.

Esper discussed the matter with senior leaders during a meeting Wednesday, including some of the legal issues surrounding a variety of bans, which some officials believe could be challenged in court.

According to the official, the new policy doesn’t undo the bans already in place. Service chiefs and secretaries will also still be able to enact additional policies restricting symbols they believe are divisive and harmful to unit cohesion. The official spoke on condition of anonymity to discuss decisions not yet made public.

Army Secretary Ryan McCarthy told reporters on Thursday that he is still working on a policy that would remove all divisive symbols from Army installations.

He didn’t mention the flag, but said, “we would have any divisive symbols on a no-fly list.”

The Associated Press contributed to this report