When's the last time a liberal SCOTUS justice dissented 3/1 with his/her peers?

Mods can move this to P&E if they think it’s too political:

By and large the Supreme Court is considered to consist of 5 conservatives - Roberts, Kavanaugh, Gorsuch, Alito and Thomas…

…and 4 liberals, Gainsbourg, Breyer, Sotomayor and Kagan.

It’s relatively easy to find examples of a conservative splitting off with his peers and joining the liberals on a decision - Roberts has done it a lot of late, for instance. But when is the last time someone like Kagan or Sotomayor defected from her 3 peers from the liberal bloc on a decision?

I don’t mean cases that are decided 9-0 or 8-1, but rather, the highly charged partisan 5-4 or 6-3 type of decision.

The most recent one I can find is Kahler v. Kansas, which was decided 6-3, with Elena Kagan joining the five conservatives in the majority, and the other three liberals in dissent.

This case was about whether a state could effectively eliminate the insanity defense without violating the 8th and 14th amendments. The court ruled that it could. Not only did Kagan break from the other liberals here, but she wrote the court’s majority opinion in this case.

The opinion was handed down in March of this year.

Thanks!

Wow, I don’t know why my phone autocorrected Ginsberg to Gainsbourg. (Facepalm)

Also note, of course, that the Supreme Court decides a lot more cases than the big famous ones everyone hears about. Most of them are based on ordinary laws, not the Constitution, and many of them don’t even have a clear “liberal side” and “conservative side”.

There was a very recent (4 days ago) 7-2 ruling with Sotomeyer and Kagan dissenting. I’m not sure why you’re looking for one liberal splitting and not two, but there are definitely ‘non block’ cases.
https://www.scotusblog.com/case-files/cases/department-of-homeland-security-v-thuraissigiam/

It was a long time ago (2003), but Justice Ginsberg joined Justice Thomas in dissenting from the majority opinion in Campbell v. State Farm. (and they were right, IMHO)

The case invented an arbitrary limit on the amount of punitive damages a jury could award. Thomas and Scalia found nothing in the Constitution that would allow the courts to impose a limit.

Although everyone likes to label the justices, they do not split liberal/conservative like everyone expects or wants them to. It’s not like the party split in Congress, where they have pressure for party loyalty. Their decisions have more to do with their philosophy about interpreting laws rather than political affiliation. At least, that’s how it’s supposed to work.

There is the ideal, and there is the modern reality. Often these days, especially on highly-politicized or controversial issues, the conservative-liberal divide on the Court is all too evident. But there are always exceptions.

The Notorious RBG’s last name is spelled “Ginsburg,” by the way.

In the recent Bostock v. Clayton County, which found that sexual orientation was a protected class, it is facile to say that Roberts and Gorsuch “joined” the liberals because they were moderate on that particular issue, but it’s clear that’s not correct, many were operating under a more philosophical than partisan bent. Kavanaugh’s dissent didn’t really make the news stories I saw, but he made it clear is that objection was that it’s a legislative and not SCOTUS scope, and that “Millions of gay and lesbian Americans have worked hard for many decades to achieve equal treatment in fact and law […] and can take pride in today’s result.”

Not to hijack, but Kansas still has an insanity defense available, where a defendant’s mental condition prevents him from forming the intent required by the offense. What the state eliminated was what is often referred to as a moral-defect test for legal insanity – that a defendant could not tell right from wrong. The Court held that the state was permitted to structure its insanity test in that way.

Here is my nomination:

Majority: Thomas, Kennedy, Breyer, Alito, Roberts
Dissent: Scalia, Ginsburg, Sotomayor, Kagan

Wow, doesn’t get better than that.