Timothy McVeigh, later convicted in the car bombing of the Alfred P. Murrah Building in Oklahoma City, is escorted from the Noble County Courthouse in Perry, Okla., on April 21, 1995. (David Longstreath/AP)

Timothy McVeigh was known in the Army as disciplined and motivated but awkward toward many people and hostile to the black soldiers he led. He shined in evaluations but failed in an attempt to join the Special Forces because of an injury, and left the service disillusioned in 1991.

The tall, rail-thin veteran kept his Army-style haircut, but floated through life rudderless. He found infamy on April 19, 1995, detonating a truck bomb outside the Alfred P. Murrah Federal Building in Oklahoma City that killed 168 people and wounded 600 more. He’d grown furious with the U.S. government and democracy in general, writing in a letter to the editor in 1992 that “AMERICA WAS IN DECLINE,” according to a Washington Post profile of him published after the bombing.

That history is salient now as the United States and the military cope anew with white extremism.

While racism has been repeatedly rejected by top military officials, the U.S. government has long been concerned about some service members and veterans joining right-wing extremist or white supremacist groups, or acting out their ideologies. A 2009 Homeland Security report cited “disgruntled military veterans” as one group to watch, prompting a backlash among some of them and an eventual apology from then-Homeland Security Secretary Janet Napolitano. Nonetheless, the report was not retracted.

To be sure, the percentage of veterans who subscribe to extremist views is tiny. But at least three recent veterans have been connected to the race-based melee in Charlottesville — most prominently James A. Fields Jr., 20, who served briefly in the Army, expressed admiration for Nazis and is charged with second-degree murder in the vehicular death of Heather Heyer.

Another veteran, Dillon Ulysses Hopper, served in the Marine Corps until January and then emerged as the leader of Vanguard America, a neo-Nazi hate group that marched alongside Fields in Charlottesville (Hopper was not present). Unlike Fields, who washed out of the Army in four months, Hopper was a Marine for more than 10 years, rising to the rank of staff sergeant, deploying to Iraq and Afghanistan and serving as a recruiter for Recruiting Station Charleston, S.C., from 2011 to 2014.

The third veteran to emerge with connections to Charlottesville is Nathan Damigo, 31, a former Marine corporal who was deployed to Iraq twice and saw combat, according to military records. The website Task & Purpose reported Thursday that he was invited to speak at the rally. The Southern Poverty Law Center has previously identified him as the founder of the white supremacist group Identity Evropa, which he started after being jailed for armed robbery.

Reports of Hopper’s past as a Marine Corps recruiter surfaced Monday, and the service confirmed it Tuesday. Within hours, the service’s top officer, Gen. Robert B. Neller, issued a condemnation of racism and extremism and said it had no place in his service.

“Our core values of Honor, Courage, and Commitment frame the way Marines live and act,” Neller said in a statement. “Bigotry and racial extremism run contrary to these core values.”

The statement was seen by some observers as a reaction to President Trump’s news conference that afternoon, in which he appeared to equate the actions of white supremacists in Charlottesville with those who opposed them. But in reality, Neller was reacting to the news about Hopper, said Lt. Col. Eric Dent, a spokesman for the general.

Neller was the second service chief to weigh in about Charlottesville, following Navy Adm. John M. Richardson, who condemned the gathering of white supremacists Saturday. Other service chiefs followed — all looking to make it clear that racism is not welcome in the military.

The Marine Corps also has sought to reassure people that those who Hopper helped bring into the service have been thoroughly screened. No one recruits alone, and a “multilayered, policy-based approach to screening” is used with several individuals at different levels interviewing prospective Marines, said Lt. Col. John Caldwell, a Marine spokesman.

The service released a statement from Hopper’s former supervisor, Staff Sgt. Kristin Chambasian, in which she said she has stayed in touch with their former recruits and none has shown any indication of harboring racist views.

“I cannot speak to when or what changed in Sgt. Hopper that resulted in his recent and current life choices, but I can say without a doubt that the Marines recruited by him and everyone else in [Recruiting Station] Charleston are a diverse population of young men and women who passed rigorous and thorough screening, interviewing, and training to earn the title of United States Marine,” her statement said.

It’s an ugly return to the past for the Pentagon, which took steps  to stamp out extremism in the 1990s, especially after the Oklahoma City bombing and the 1995 murder of a black couple near Fort Bragg, N.C. In that case, two soldiers — Malcolm Wright Jr. and James N. Burmeister — were found with a Nazi flag and white supremacist pamphlets. They were eventually convicted.

The military now screens recruits closely for tattoos that show hints of extremist ideology, but that does not catch every potential problem. In one example, the Army this year enlisted Guillaume Cuvelier, 29, who fought alongside Russian-backed separatists in Ukraine and participated in far-right politics in Europe. He was a member of the 25th Infantry Division in Hawaii when The Washington Post published a story about him in May, and he was subsequently discharged from the service.

Meanwhile, the services are still grappling with what to do with the incorporation of Confederate history into military culture. Ten Army bases are named after generals who fought for the South during the Civil War, including Fort Bragg, Fort Hood, Fort Polk and Fort Benning. The Army said two years ago that there was “no discussion of adjusting the naming policy,” and did not respond to numerous requests this week for comment about whether that has changed.

In the Navy, a ship is named the USS Chancellorsville, one of the greatest victories for the Confederacy during the Civil War. A Navy official, speaking on the condition of anonymity to discuss internal debate at the Pentagon, said it is unlikely the service will rename the ship. But it is possible that the Navy could change its coat of arms, a logo that includes a wreath commemorating the death of Gen. Thomas “Stonewall” Jackson, a Confederate officer who was mortally wounded in the battle.