President-elect Joe Biden’s selection of Gen. Lloyd J. Austin III to serve as defense secretary is already mired in controversy, as Democrats from across the party’s political spectrum worry about undermining the tradition of civilian leadership at the Pentagon.

Austin, who retired in 2016 as a four-star general after leading U.S. Central Command, has not been out of uniform for the seven years required by law to serve as Pentagon chief. As such, the House and Senate would need to approve a waiver — a workaround that is supposed to be reserved only for exceptional circumstances — to allow him to assume the position.

Congress has passed such a waiver only twice, most recently to allow President Trump’s first defense secretary, Gen. Jim Mattis, to take office in 2017. For a party that campaigned on restoring norms it says Trump undermined or tried to dismantle, two waivers in four years represents a pattern some are loath to approve.

President-elect Joe Biden plans to name retired Gen. Lloyd J. Austin III to be defense secretary. If confirmed, Austin would be the first Black Pentagon Chief. (Reuters)

Choosing another recently retired general to serve in a role that is designed for a civilian just feels off,” Rep. Elissa Slotkin (D-Mich.), who worked with Austin during a CIA deployment to Iraq, said in a statement Tuesday.

But others say the Mattis precedent makes it impossible to deny Austin the same opportunity.

“Having Mattis get a waiver three years ago and then saying to one of the more qualified African American generals, the first African American secretary of defense, that somehow a waiver doesn’t work for you is hypocritical,” Rep. Ro Khanna (D-Calif.) said in an interview. While Khanna voted against a waiver for Mattis, he plans to vote in favor of a waiver for Austin, he said — and “hopefully the situation will never arise again.”

Congress first created the rule dictating the length of time military officers must spend out of uniform before being eligible to lead the Defense Department in 1947. At that point, the cooling-off period was 10 years. In 2008, it was shortened to seven. There are some members of Congress who say no limit should exist at all.

“I always support waivers. Because I don’t believe that we should have the seven years in there anyway,” Sen. James M. Inhofe (R-Okla.) told reporters Tuesday. Inhofe chairs the Senate Armed Services Committee, which will consider Austin’s nomination.

But for the most part, Democrats and Republicans approach the concept of waivers with a measure of unease.

“I do believe that there needs to be some distance between the nominee and their service,” Sen. Joni Ernst (R-Iowa) told reporters Tuesday, noting that while she was “glad” she had supported a waiver for Mattis, it was a “hard” decision.

Nearly four years ago, lawmakers approved Mattis’s waiver for his military credentials, but also because the larger-than-life general was seen as someone who could serve as a check on Trump’s more rash impulses. Austin, who has kept a lower profile despite his stewardship of one of the military’s most conflict-ridden command zones, is seen as someone who is more likely to be in lockstep with Biden.

In 2017, Sen. Jack Reed (D-R.I.), the top Democrat on the Senate Armed Services Committee, said that “waiving the law should happen no more than once in a generation” and promised that he would “not support a waiver for future nominees.” But on Tuesday, he told reporters that a waiver for Austin “has to be evaluated” and would depend on “his aptitude and qualities.”

“He’s an outstanding officer,” Reed added.

Party fealty and a sense of history appears to be having an effect on some Democrats who claimed to oppose Mattis’s waiver, but are leaving the door open to one for Austin.

“Well I opposed the waiver on Mattis, but I have to tell you I was so impressed with his performance that I would consider a waiver for Austin,” Sen. Richard J. Durbin (D-Ill.), the Senate’s second-highest ranking Democrat, told reporters Tuesday.

“As the first Black secretary of defense, General Austin — who has broken barriers throughout his career — would lead the most diverse military in our nation’s history,” said Rep. Anthony G. Brown (D-Md.), the vice chairman of the House Armed Services Committee, adding that Biden and Austin “both understand that civilian leadership, authority and control of the military is vitally important to the strength of our democracy.”

Four years ago, Brown joined the vast majority of House Democrats in opposing Mattis’s waiver — a stand due in no small part to the fact that Mattis never testified before the House Armed Services Committee ahead of the vote. Although it is customary for the Senate alone to hold pre-confirmation hearings, many members thought the unique circumstances of the waiver necessitated an audience in the House, too.

In a statement Tuesday, Rep. Adam Smith (D-Wash.), the committee chairman, said he was “concerned about again appointing a recently retired General to be Secretary of Defense” and that Austin “should meet with members of the House Armed Services Committee so they can ask questions about civilian control of the military, and to be assured that General Austin is committed to this important principle.”

It is not clear whether Biden’s team intends to comply with Smith’s request.

Some Democrats who opposed Mattis’s nomination committed themselves Tuesday to vote against Austin’s waiver on principle.

“It is exciting and historic, but I believe that a waiver of the seven-year rule would contravene the basic principle that there should be civilian control over a nonpolitical military,” Sen. Richard Blumenthal (D-Conn.) told reporters. “It, I think, has to be applied — unfortunately — in this instance. … I will not support the waiver.”