Justices often write separately to express their disagreement with the reasoning in the majority opinion. Under the long-established practice, whether such a separate opinion is a concurrence in the judgment or a dissent turns entirely on whether it reaches the same bottom-line judgment as the majority—i.e., affirm, reverse, reverse and remand with specific instructions.
I have had occasion recently to be surprised by lapses from this practice, and I’m even more astonished to learn that Chief Justice Roberts, whom I would have thought to be a staunch formalist on this matter, has himself deviated from it. As law professor Richard Re explains in an interesting post, the Chief denoted his separate opinion in National Pork Producers Council v. Ross (2023) as “concurring in part and dissenting in part” when he was in fact “simply dissenting with respect to the Court’s judgment.” Re speculates that the Chief’s mislabeling “may have been a bid to strengthen his opinion’s claim to precedential authority.”
Today’s supposed “dissent” by Justice Sotomayor in Department of State v. Muñoz is another striking example. Sotomayor (joined by Justices Kagan and Jackson) actually agrees with Justice Barrett’s majority opinion that the judgment of the Ninth Circuit should be reversed. She objects only that the majority opinion should have done so “on narrow grounds under longstanding precedent.” (Dissent at 1; see also p. 10 (“That could and should have been the end of it”).) So she is concurring in the majority’s judgment of reversal.
There is a twist here that would warrant denominating Sotomayor’s opinion as “concurring in the judgment in part and dissenting in part.” Specifically, in addition to reversing the Ninth Circuit’s judgment, the majority remands the case “for further proceedings consistent with this opinion.” From what I can tell, under both Barrett’s holding and Sotomayor’s alternative, the only option for the Ninth Circuit on remand is to affirm the district court’s grant of summary judgment to the State Department. But because Sotomayor believes that any “further proceedings” should be “consistent with [her] opinion,” not with Barrett’s, she would dissent from that part of the judgment. [Addendum (6/22): A law professor suggests to me that the “for further proceedings …” phrase should not properly be considered part of the judgment. If it’s not, then Sotomayor’s opinion is simply and entirely “concurring in the judgment.”]
It would seem that the justices have broadly acquiesced in this sloppiness—Barrett, for example, repeatedly refers to Sotomayor’s opinion as “the dissent”—and the Court’s reporter of decisions is evidently fine on it (or extremely inattentive, which seems unlikely). I note, though, that in another case decided today, Smith v. Arizona, Justice Alito (joined by the Chief), vigorously disagreed with the majority’s approach (“the Court inflicts a needless, unwarranted, and crippling wound on modern evidence law”) while properly labeling his opinion as “concurring in the judgment.” So the Court’s current approach to the elementary question of what is a dissent appears to be chaotic.