The Senate Armed Services Committee has approved a waiver that would allow retired Gen. James Mattis to serve as the Secretary of Defense under Donald Trump. The waiver now goes to the Senate for a full vote.

Just three committee members — Democratic Sens. Kirsten Gillibrand (N.Y.), Richard Blumenthal (Conn.) and Elizabeth Warren (Mass.) — voted against the waiver.

Current law says Pentagon chiefs must be out of uniform for at least seven years. The law has been waived just once, for George Marshall in 1950.

The committee voted immediately after Mattis’ confirmation hearing, in which he sought to make clear he understands the difference between civilian leadership and military service.

The committee’s chair, however, said not to expect this to be a frequent thing.

Sen. Jack Reed (D-R.I.), ranking member of the committee, expressed concern about giving the Mattis the exception, but said his testimony Thursday and his general character convinced him to vote for it. Still, Reed said he won’t support a similar waiver for any future nominees.

Which is an understandable and, frankly, smart decision. This is not the best precedent to set, but it is a solid pickup for the Department of Defense.