In Children's Hosp. Ass'n of Texas v. Azar, 933 F.3d 764, 770-71 (D.C. Cir. 2019), the D.C. Circuit reaffirmed its skepticism of the expressio unius canon in Chevron cases:
To conclude otherwise, we would have to rely on the interpretive canon expressio unius est exclusio alterius, which means “expressing one item of [an] associated group or series excludes another left unmentioned.” Chevron U.S.A. Inc. v. Echazabal, 536 U.S. 73, 80, 122 S.Ct. 2045, 153 L.Ed.2d 82 (2002) (alteration in original) (quoting United States v. Vonn, 535 U.S. 55, 65, 122 S.Ct. 1043, 152 L.Ed.2d 90 (2002)). But that canon has been called a “feeble helper in an administrative setting.” Adirondack Med. Ctr. v. Sebelius, 740 F.3d 692, 697 (D.C. Cir. 2014) (quoting Cheney R. Co. v. ICC, 902 F.2d 66, 69 (C.A.D.C. 1990)). And, in any setting, it “applies only when ‘circumstances support[ ] a sensible inference that the term left out must have been meant to be excluded.’” N.L.R.B. v. SW Gen., Inc., ––– U.S. ––––, 137 S. Ct. 929, 940, 197 L.Ed.2d 263 (2017) (quoting Echazabal, 536 U.S. at 81, 122 S.Ct. 2045); see also Barnhart v. Peabody Coal Co., 537 U.S. 149, 168, 123 S.Ct. 748, 154 L.Ed.2d 653 (2003) (“[W]e do not read the enumeration of one ... to exclude the other unless it is fair to suppose that Congress considered the unnamed possibility and meant to say no to it.”).
The D.C. Circuit has also acknowledged that this “canon operates differently in [the court's] review of agency action than it does when [it is] directly interpreting a statute.” Van Hollen v. FEC, 811 F.3d 486, 493 (D.C. Cir. 2016); see also Mobile Commc'ns Corp. of Am. v. FCC, 77 F.3d 1399, 1405 (D.C. Cir. 1996) (expressio unius is “too thin a reed to support the conclusion that Congress has clearly resolved an issue.”) (cleaned up).
That got me wondering: What do the other circuits say? I found a couple of cases that appear to demonstrate that other circuits--including the Fifth--disagree with the D.C. Circuit on this important nuance of statutory interpretation. See, e.g., Waggoner v. Gonzales, 488 F.3d 632, 636 (5th Cir. 2007); Blandino-Medina v. Holder, 712 F.3d 1338, 1345 (9th Cir. 2013). If you know of other circuits that have taken sides on this question, or if you have strong views on the matter, let me know in the comments.