Lloyd Austin will begin courtesy calls with Congress next week, but his nomination to be Defense secretary may not even make it out of committee unless Republicans help grant the waiver he needs to hold the job, people familiar with the matter say.

The big picture: While civil rights groups are hailing Austin’s nomination to be the first Black Defense secretary, some Democrats on the Senate Armed Services Committee have already said they oppose the waiver, leaving it up to Republicans to rescue him — and some predict the vote will fail in committee.

The close math could mean Austin's confirmation hinges on his public testimony, especially about how he'll ensure civilian control over the military. The retired general needs a waiver because he has not been out of the armed forces for more than seven years.

• "We have been gratified by the support secretary-designate Austin has received from lawmakers of both parties," said a transition official. "We are confident his barrier-breaking nomination will garner the support it deserves."

By the numbers: The waiver requirement will likely create a three-step process: a vote in both the House and Senate on a bill granting it and then a vote just in the Senate on the nomination itself.

The Senate Armed Services Committee is expected to have 27 members, and if Republicans keep control of the Senate, it'll be 14 Republicans and 13 Democrats.

• Four Democrats — Sens. Elizabeth Warren, Richard Blumenthal, Kirsten Gillibrand and Tammy Duckworth — have publicly indicated they won’t support a waiver.
• Sen. Jack Reed, the top Democrat on the committee, is noncommittal. He voted in 2017 to approve a waiver for James Mattis, President Trump's first secretary of Defense, but said, “I will not support a waiver for future nominees."
• In a statement last week, Reed said, "One cannot separate the waiver from the individual who has been nominated."
• On the Republican side, Sen. Tom Cotton expressed "real reservations" for the waiver in a Fox interview, and Chair Jim Inhofe has only offered mild public support.

In the House, Democrats are in the majority and hold a narrow margin on the Armed Services Committee.

Axios' Alayna Treene reports that some Senate Republicans have floated the idea of voting for the waiver but against Austin. That would help them avoid charges of hypocrisy for supporting the Mattis waiver.

• Hill aides told Alayna that Austin's military prowess and gripping speech after Biden announced his nomination this week earned him major brownie points with both parties.

The reverse also could happen: Some Democrats could oppose the waiver but approve the nomination.

• Gillibrand appeared to leave herself some wiggle room. “I am not," approving a waiver, she told Axios' Kadia Goba, "but I will meet with him and review his qualifications for the job.”

Flashback: Mattis’ waiver passed 81-17 in the Senate and 268-151 in the House, with key Democratic senators including Cory Booker, Bernie Sanders, Dick Durbin, Chris Murphy and Duckworth voting no.

• “How can anyone justify voting for a different outcome for a highly qualified Black man compared to how Mattis was treated?” Rep. Ro Khanna (D-Calif.) tweeted.