Defense Secretary Mark T. Esper effectively banned displays of the Confederate battle flag on U.S. military installations, saying in a memo released Friday that the American flag is the “principal flag we are authorized and encouraged to display.”

The memo did not explicitly mention Confederate banners but stated that 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.”

Esper chose not to specify which flags were prohibited to ensure that “the department-wide policy would be apolitical and withstand potential free speech political challenges” and that the services were “free to act on other flags,” a defense official said.

The official, speaking on the condition of anonymity because of the sensitivity of the issue, said the White House is aware of the new policy. But it was not immediately clear whether President Trump, who has pushed to preserve Confederate symbols, supports the change.

Attacks on statues of enslavers, Confederate generals and others reflect the symbolic place they hold worldwide in the history of and fight against racism. (The Washington Post)

The decision comes amid a nationwide conversation about race and racism that was spawned by the killing of a black man, George Floyd, in police custody in May. But the discussion in the Pentagon began before that, when Gen. David H. Berger, commandant of the Marine Corps, announced in April that he was banning the public display of the Confederate battle flag on Marine bases.

The policy was issued after a tense period between Trump and Esper following the president’s threat to invoke the Insurrection Act to deploy active-duty military forces to quell unrest prompted by Floyd’s death. Esper and Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, opposed the idea, and Trump considered firing his defense secretary, administration officials said.

The Marine Corps released its new policy banning the Confederate battle flag shortly afterward, and other senior military officials expressed interest in following suit. But deliberations in the other services came to a halt last month after Trump lashed out on Twitter in response to Esper and Army Secretary Ryan D. McCarthy acknowledging that they were open to changing the names of 10 Army installations that carry the monikers of Confederate officers who fought to preserve slavery.

An amendment in the new defense spending bill would require the Pentagon to change the base names as well as remove other Confederate references, symbols and paraphernalia from installations within three years. Trump has threatened to veto the bill if the amendment is included.

In his memo Friday, Esper sought to cast his decision as an affirmation of the American flag and what it means. He did not mention the base-naming issue.

“Flags are powerful symbols, particularly in the military community for whom flags embody common mission, common histories, and the special, timeless bond of warriors,” Esper said in his memo, which was obtained by The Washington Post. “As Supreme Court Justice John Paul Stevens, a veteran of the Second World War, once wrote about the United States flag: ‘It is a symbol of freedom, of equal opportunity, of religious tolerance, and of good will for other peoples who share our aspirations.’ ”

Esper said that in addition to the American flag, several others are authorized, including those of U.S. states and territories, the District, military services, general officers, Senate-confirmed presidential appointees, American allies and partners, and organizations such as NATO in which the United States is a member, as well as the POW/MIA flag.

Confederate flags are absent from that list.

It was not clear how the new policy may affect other flags that were not explicitly authorized, such as specific flags that military units have, the rainbow gay pride flag and the Gadsden flag, which features a yellow field, a rattlesnake and the phrase “Don’t tread on me.” The Gadsden flag’s roots can be traced to soldiers in the Revolutionary War, but it also is frequently used to express anti-government sentiment.

One organization championing LGBTQ rights, the Modern Military Association of America, sounded the alarm about the new policy.

“The Pentagon must immediately reconsider and take swift and appropriate action to ensure the Pride flag and LGBTQ Pride Month observances are not threatened,” Jennifer Dane, the group’s interim executive director, said in a statement. “If Secretary Esper refuses to reconsider, we will call on Members of Congress to take action.”

In recent days, Esper has announced several steps to address racial inequity in the Pentagon while keeping a low profile in the media. They include banning photographs from consideration in promotion packages, developing new unconscious-bias training, and reviewing hairstyle and grooming policies for racial bias.

Esper also announced the creation of the Defense Department Board on Diversity and Inclusion, which met for the first time Wednesday.