Like the country it serves, the U.S. military is fighting an internal battle against racism, Chairman of the Joint Chiefs of Staff Gen. Mark Milley said Thursday, but old names and symbols of that enemy are present and strong enough to sow division.

“Divisiveness leads to defeat,” Milley told the House Armed Services Committee.

“There is no place in our armed forces … for symbols of racism, bias or discrimination.”

The Civil War was an “act of treason,” he said. The south’s military leaders betrayed their nation profoundly, and still, many military installations bear their names, according to Milley.

“It was an act of treason at the time against the union, against the stars and stripes, against the U.S. Constitution, and those officers turned their back on their oath.”

The military has been under pressure for years to change the names of bases like Fort Bragg, in North Carolina, or Fort Benning, in Georgia, but those calls have been especially loud over the last few months as nationwide protests force the country to confront its racist past and present.

In all, there are at least 10 military installations named for members of the Confederacy, according to Military.com.

Milley has ordered a military commission to look into the issue and explore potentially changing the names.

“The way we should do it matters as much as that we should do it,” Milley said.

Nearly half of America’s armed forces, 43%, are members of minority groups, according to Milley, and at least 20% are Black. A name can be more than just a name, particularly when that name is Gen. Braxton Bragg, or Gen. John Bell Hood, he said.

“For those young soldiers that go on to a base of Fort Hood, Fort Bragg, whatever, named after a Confederate general, they can be reminded that that general fought for an institution of slavery,” Milley said.

“I had a staff sergeant when I was a young officer who actually told me that at Fort Bragg. He said he went to work every day on a base that represented a guy who enslaved his grandparents.”

Milley’s efforts put him at odds with president Donald Trump, who has vowed he will “not even consider” allowing the bases to be renamed, McClatchy News reported.

“These monumental and very powerful bases have become part of a great American heritage, and a history of winning, victory and freedom,” Trump said in a tweet.

“Our history as the greatest nation in the world will not be tampered with. Respect our military!”