Retired Gen. Lloyd J. Austin III vowed Tuesday to eradicate extremism in the ranks if confirmed as the next defense secretary, as the Pentagon struggles to address a growing internal threat in the wake of this month’s riot at the U.S. Capitol.

“We can never take our hands off the wheel on this,” Austin, who would become the country’s first African American Pentagon chief, told lawmakers considering his nomination by President-elect Joe Biden. “This has no place in the military of the United States of America.”

Austin, who before his 2016 retirement served as head of U.S. Central Command and previously commander of U.S. troops in Iraq, made reference to a consequential episode earlier in his career when, as a young officer in the 82nd Airborne Division, a network of skinhead soldiers was uncovered following the murder of an African American couple near the division’s base.

Nearly two dozen soldiers were later found to have links to neo-Nazi or extremist groups. A distressing realization, Austin said, was that military leaders hadn’t picked up on signs about the threat. “We just didn’t know what to look for,” he said.

Austin’s reference to the 25-year-old incident signifies the urgency of the military’s challenge today in identifying and addressing anti-government and racist currents, among the numerous issues he will face if he becomes Biden’s Pentagon chief.

Austin, who since his retirement has stayed out of the political fray, will face a host of other challenges, including accelerating the effort to effectively compete against China, winding down insurgent wars, and repairing defense alliances strained by hostility from President Trump. He will also have to grapple with a flattened defense budget and improve morale among a Pentagon workforce buffeted by leadership upheaval.

Before any of that can occur, however, Austin must surmount an additional hurdle in the form of attaining a congressional waiver to a requirement that defense secretaries be out of the military for at least seven years.

After Trump’s election in 2016, lawmakers voted to approve a waiver for Jim Mattis, another former commander who had been retired for less than seven years, as defense secretary — only the second time such an exception had been granted. But some Democrats voiced discomfort with the move, fretting that it would undermine the U.S. tradition of civilian control of the military.

“I know that being a member of the president’s Cabinet — a political appointee — requires a different perspective and unique duties from a career in uniform,” Austin said.

While several senators, including Tom Cotton (R-Ark.), Elizabeth Warren (D-Mass.) and Tammy Duckworth (D-Ill.), have said they would oppose granting Austin the waiver, which also needs the approval of the House of Representatives, Austin is expected to receive the dispensation and be confirmed.

Because a final confirmation vote is not expected until Friday at the earliest, David Norquist, currently deputy defense secretary, will serve as acting Pentagon chief until Austin is in place, a transition official said on the condition of anonymity to discuss internal plans.

How effectively Austin can transform into a political being after a long career in uniform remains to be seen. Trump’s two confirmed defense secretaries, Mattis and Mark T. Esper, regularly sought to steer the military away from political fights but were sometimes criticized for appearing as if they remained in uniform themselves, citing the apolitical position of the military and “best military advice” despite their inherently political role.

Austin emphasized that he would surround himself by career civilians rather than former military officers, in contrast to Mattis, who filled many of the top-level civilian positions across the Pentagon with former uniformed officers.

Austin, 67, the son of a postal worker and a homemaker from Thomasville, Ga., comes under a renewed congressional spotlight after a career in which he repeatedly broke racial barriers at the department, including serving as the first Black officer to command an infantry division in combat, head Central Command and serve as vice chief of staff of the Army.

“There is kind of a sad commentary here, and that is: It shouldn’t have taken us this long to get here. There should have been someone who preceded me,” Austin said in a video released by the Biden campaign in which he described pioneering African American troops, including the Tuskegee Airmen and the Montford Point Marines. “My goal is not to be the last.”

Austin spoke as the current Pentagon leaders promise to take on what they acknowledge is a serious problem with support for white nationalism and anti-government movements in the military community. The issue has come under renewed scrutiny after the Jan. 6 attempted insurrection at the Capitol, in which a pro-Trump mob including a number of current and former members of the military stormed Congress as lawmakers gathered to certify Biden’s electoral win.

On Tuesday, officials said a dozen members of the massive National Guard force assembled to help secure Biden’s inauguration had been removed from duty, at least several of whom were believed to have sympathies for anti-government groups.

Austin said that the military should more effectively screen recruits for extremist ties and that it can also make sure leaders across the department are attuned to what their subordinates are doing, reading and thinking to ensure that everyone is embracing the values of the U.S. military.

“I also think we need to do a better job of, once we have people on board, that we are paying attention to them, that we are creating the right kind of environment for them to live in and that they are embracing the values that we think are important in the military and the values that are important for this country,” he said.

Austin is also likely to face ongoing scrutiny over his ties to the defense industry, including his position as a member of the board of directors of weapons manufacturer Raytheon, whose bombs have been linked to Saudi airstrikes on civilian sites in Yemen.

Warren pressed Austin on his membership on the boards of Raytheon and United Technologies after retiring from the military. Austin agreed to extend his recusal on matters involving Raytheon for four years and said he wouldn’t serve on any defense contractor boards or become a lobbyist after leaving the Pentagon for a second time.

“Quite frankly, I’ll be too old to sit on the board of a defense contractor after my service. I have no intent to be a lobbyist, as well,” he said.

Warren thanked Austin for being willing to operate under more constraints than are currently required by law. “Going above and beyond what federal law requires, as you are doing here, sends a powerful message that you are working on behalf of the American people and no one else,” Warren said.

Before retiring, Austin kept a lower public profile than other senior officers, declining to invite reporters to join his tours of the Middle East, as other Centcom commanders have done. That decision reduced public visibility into the activities of American troops operating in the region. In response to questions on the matter, Austin promised to conduct regular briefings and TV interviews and be open to the media as defense secretary.

Alex Horton, Dan Lamothe and Karoun Demirjian contributed to this report.