Today’s Supreme Court decision in  Mayorkas v. Cuellar de Osorio, an immigration case, produced an interesting line-up. In this case five justices agreed that the board of Immigration Appeals’ interpretation of the relevant statutory provisions was reasonable, though they disagreed as to whether the statute contained an internal conflict and, if so, whether the BIA has the authority to resolve such a conflict.  The opinion is here.

Justice Kagan announced the judgment of the Court, but her opinion was only joined by Justices Kennedy and Ginsburg. Chief Justice Roberts concurred in the judgment separately, joined by Justice Scalia. Justice Sotomayor wrote one dissent, joined by Justice Breyer and (save for one footnote) Justice Thomas. Justice Alito wrote the other dissent.  

What could be so wrong with a footnote that Justice Thomas refused to join it?  It’s a good question.  Here’s the text of the note in question, footnote 3.

To understand the kind of conflict that can make deference appropriate to an agency’s decision to override unambiguous statutory text, consider the provisions at issue in National Assn. of Home Builders v. Defenders of Wildlife, 551 U. S. 644 (2007). One provision, §402(b) of the Clean Water Act, 33 U. S. C. §1342(b), commanded, “without qualification, that the [Environmental Protection Agency] ‘shall approve’ a transfer application” whenever nine exclusive criteria were satisfied. 551 U. S., at 661. A second provision, §7(a)(2) of the Endangered Species Act of 1973, 16 U. S. C. §1536(a)(2), was “similarly imperative,” ordering “ ‘[e]ach Federal agency’ ” to ensure that its actions were “ ‘not likely to jeopardize’ ” an endangered species. 551 U. S., at 662. “[A]pplying [§7(a)(2)’s] language literally,” we observed,would contravene the “mandatory and exclusive list of [nine] criteria set forth in §402(b),” because it would “engraf[t] a tenth criterion onto”the statute. Id., at 662–663. The agency accordingly could not “simultaneously obey” both commands: It could consider 9 criteria or 10, but not both. Id., at 666. In that circumstance, we found it appropriate to defer to the agency’s choice as to “which command must give way.” Ibid.

The opinion Justice Sotomayor cites here — NAHB v. Defenders of Wildlife — was joined by Justice Thomas (but not by Sotomayor).  So one possibility is that Justice Thomas simply objects to how the footnote characterizes the opinion, suggesting it provides authority for an agency to ignore clear statutory text when necessary to resolve a statutory conflict.  Another is that Justice Thomas thought NAHB inapposite here because it involves a potential conflict between two separate statutes, rather than a conflict within a single statute.

A third, more intriguing, possibility, is that the argument in this footnote is relevant to another pending case in which an agency is confronted with a conflict within a statute that the agency used as a justification to ignore clear statutory text.  UARG v. EPA — the big greenhouse gas case argued earlier this term — is just such a case.  Note further that here five justices — the four liberals and Justice Kennedy — join opinions allowing agencies to resolve potential statutory conflicts in this way.  Is this a clue to the outcome in UARG?  We’ll have to wait and see.