WILMINGTON, Del. – Calling him “a leader of extraordinary courage, character, experience and accomplishment,” President-elect Joe Biden on Wednesday formally introduced his pick for defense secretary, retired four-star Army Gen. Lloyd Austin.

Biden and Austin, 67, have a history working together while Biden was vice president and Austin led U.S. troops in Iraq from 2010-11 and later served as the Army’s vice chief of staff. 

Biden described Austin, who spent more than 40 years in the Army, as "someone with whom I have worked closely for many years and I've seen perform to the highest standards under intense pressure."

Austin’s military resume is undoubtedly strong. But his nomination is raising concerns, even among Democrats, because the National Security Act requires civilian control of the Pentagon. 

Lloyd would need a waiver from Congress since he has been retired from active-duty military service for less than seven years. In 2017, lawmakers approved a waiver for Gen. James Mattis to serve as President Donald Trump's defense secretary. 

Biden and Lloyd did not dodge the issue at Wednesday’s announcement. Pleading his case, the president-elect said he understands and respects the law, but that he believes Austin’s leadership is needed at “this moment in our history.”

“I believe in the importance of civilian control of the military,” Biden said. “So does the secretary designee, Austin. He'll be bolstered by a strong and empowered civilian sector and senior officials working to shape DOD's policies and ensure that our defense policies are accountable to the American people.

"So just as they did for Secretary Jim Mattis, I ask the Congress to grant a waiver for Secretary Designee Austin,” Biden continued. “His many strengths and his intimate knowledge of the Department of Defense and our government, I think, are uniquely suited for the challenges we face now, the crisis we face now. He is the person we need at this moment, in my view. And given the urgent threat and challenges of our nation's forces, he should be confirmed swiftly.”

A number of Democratic lawmakers spoke out against President-elect Joe Biden's nominee for Secretary of Defense, Gen. Lloyd Austin, ahead of his official announcement event.

Sen. Tammy Duckworth (D-IL) told MSNBC Wednesday that she "will not vote for the waiver," though she called Austin a "very capable" candidate. Sen. Richard Blumenthal (D-CT) told Politico that he too would not support a waiver.

Sen. John Tester (D-MT) said that he did not vote for Mattis' waiver, and "I don't think I will" for Austin.

Other Democrats were slightly more ambivalent about their final decision, but expressed skepticism about the waiver.

Sen. Jack Reed (D-RI), the ranking Democrat on the Senate Armed Services Committee, said in a statement that ultimately "the burden of proof is on the administration and it also comes down ultimately to the quality of the nominee," but said "the preference would be for someone who is not recently retired."

Sen. Brian Schatz (D-HI) said that while "it is difficult to imagine voting for a Mattis waiver and not an Austin waiver," he did not like the "trend" of issuing such waivers to block civilian control of the Pentagon.

Sen. Tim Kaine (D-VA) said he has "great respect" for Austin, but "I intend to closely evaluate the implications for waiving the National Security Act requirement twice in just four years.”

Sen. Elizabeth Warren (D-MA), Biden's one-time primary opponent, said, "I don't think we ought to be doing these waivers." However, she did also say that Austin's "career has been exemplary," and she looks forward to "meeting him and talking to him more."

In addition to protecting national security, Austin will be key in distributing COVID-19 vaccines, Biden said.

Austin, who retired in 2016, said he believes he would be entering the job “as a civilian leader, with military experience, to be sure, but also with a deep appreciation and reverence for the prevailing wisdom of civilian control of our military."

If confirmed, Austin would become the nation’s first Black defense secretary. 

"Through sheer determination and extraordinary skill, he's been breaking down barriers and blazing a trail forward in this nation for many years now, for more than 40 years,” Biden said. “And he has a long way to go, and he's going to do it again."

Austin said he is grateful for those who helped paved the way for his potentially historic confirmation, including Henry Ossian Flipper, who in 1877 became the first African American to graduate from the United States Military Academy at West Point and came from Austin’s hometown of Thomasville, Georgia.

Austin quoted Isaac Newton, saying, "If I have seen a little further, it is by standing on the shoulders of giants.”

He said he “fervently” believes in building strong alliances and that his top priority would always “be the men and women, military and civilian, who make up the department and their families.”

"Over the past four decades, I've witnessed our service members and civilians' selflessness and patriotism and the extraordinary lengths that they will go to in support of the mission and in support of one another,” he said. “And I could not be more proud of them and their families. And if confirmed, it will be the honor of my lifetime to lead them again with honor and integrity."