[DoodleDawg]

CNN reports that Mattis would just need a waiver from Congress - something that he’d likely be able to get.

And CNN is never wrong are they? Here's the law in question: 10 U.S. Code § 113 Where does it say it can be waived by Congress?

[MountainWalker]

The only limitations on Congress are of the constitutional variety without an amendment. Whatever that statue says can be overridden with a waiver passed through both houses and signed by the executive. Period.

[9YearLurker]

Congress makes the laws and Congress can change the laws.