PROVIDENCE, R.I. (WPRI) — Four years ago, when President-elect Trump selected a recently retired general as his first defense secretary, U.S. Sen. Jack Reed grudgingly went along.

While Reed maintained he had the highest respect for Trump’s pick, James Mattis, he expressed concern that it would set a bad precedent for civilian control of the military to grant Mattis a waiver from the federal law that bars recently retired officers from leading the Pentagon.

Reed also made clear it wouldn’t happen again. “Waiving the law should happen no more than once in a generation,” he said in early 2017. “Therefore I will not support a waiver for future nominees.”

But now Reed, the top Democrat on the Senate Armed Services Committee, is being asked to do the same thing by an incoming president of his own party — and he’s changing his tune as all of Washington watches.

President-elect Biden is set to nominate retired Gen. Lloyd Austin as defense secretary. Austin, who is said to be widely respected on Capitol Hill, would be the first Black American to lead the world’s largest military.

“I hope that Congress will grant a waiver to Secretary-designate Austin, just as Congress did for Secretary Jim Mattis,” Biden wrote in an Atlantic essay Tuesday. “Given the immense and urgent threats and challenges our nation faces, he should be confirmed swiftly. … He is the person we need in this moment.”

In a statement Tuesday night, Reed signaled his openness to granting Austin a waiver, though he did not outright say he would vote to do so. The Armed Services Committee’s Republican chairman, James Inhofe, has already expressed his own support.

“It is the obligation of the Senate to thoroughly review this nomination in the historic context it is being presented and the impact it will have on future generations,” Reed said of Austin. “Indeed, one cannot separate the waiver from the individual who has been nominated.”

Longtime Reed watchers see the five-term senator as caught between a rock and a hard place: his firmly stated opposition to granting another waiver pitted against his desire not to make an embarrassing early break with a new president of his own party offering a historic nomination.

“As I have stated in the past, civilian control of the military is a hallmark of our Constitution and democratic system,” Reed said.

But describing Austin as “a distinguished and decorated officer whose wise counsel would be an asset to any president,” Reed went on, “I will carefully review this nomination and look forward to meeting with General Austin to hear his views on the national security challenges we face and the exemption request being made in order for him to be considered to lead the Pentagon.”

Reed’s potential change of heart will not go unnoticed by his colleagues on both sides of the aisle.

U.S. Sen. Tom Cotton, an Arkansas Republican who serves with Reed on the Armed Services Committee, had highlighted the Rhode Islander’s previously stated view in a radio interview earlier Tuesday.

“Many more senators have since expressed their regret for granting that waiver given the state of civil-military relations inside the Pentagon and up to the White House,” Cotton told the host Hugh Hewitt, referring to the Mattis nomination. “And one I would just highlight to you, Hugh, is Jack Reed.”

Reed “said it should be a once-in-a-generation moment, and that he would not in the future support another waiver for a recently retired general,” Cotton noted. “So if they’ve already lost the senior Democrat on the Armed Services Committee, you’ve got to think that they’re at risk of losing a lot of other senators.”

Ted Nesi (tnesi@wpri.com) is WPRI 12’s politics and business editor and a Target 12 investigative reporter. He is a weekly panelist on Newsmakers and hosts Executive Suite. Follow him on Twitter and Facebook