Joan Biskupic’s excellent new book, Breaking In, brings us deep insights into the most important constitutional law decisions of our era. But one bit that seems to have escaped the media was coverage over Justice Sotomayor’s concurring opinion in all-important-jurisdiction case Daimler AG v. Bauman. Forget affirmative action or the Fourth Amendment. We’re talking about RBG and Sotomayor dueling on personal jurisdiction!

Biskupic explains some of the background of the decision:

For weeks, Sotomayor had seen drafts of Ginsburg’s opinion as it circulated among the justices. She knew she was about to be a public target. But she would have the courage of her convictions— perhaps stubbornly, misguidedly— yet with confidence enough to be the one in an 8– 1 vote. A week before the Daimler opinion was handed down, in January 2014, Sotomayor told an audience of more than a thousand that to bolster her courage, she often thought about the worst thing that could happen when she undertook a challenging endeavor. She would conclude: “You know something … so what?”

In a footnote that takes up almost entire page in Daimler v. Bauman, Jusice Ginsburg singles out Justice Sotomayor for “selectively referring to the trial court record” in Perkins v.  Benguet Consol. Mining Co. (1952). Justice Sotomayor had the opportunity to pull back her dissent, in the face of withering criticism from 8 Justices, but she said, “so what.”

“So what.” That was more-or-less my reaction to reading Sotomayor’s dissent.