Below, Sarah Isgur shares five key insights from her new book, Last Branch Standing: A Potentially Surprising, Occasionally Witty Journey Inside Today’s Supreme Court.
Sarah is an ABC News legal analyst, editor of SCOTUSblog, and co-host of Advisory Opinions, the nation’s top legal podcast. She served in the DOJ as the director of the Office of Public Affairs, helped run Carly Fiorina’s presidential campaign, and clerked for Judge Edith H. Jones of the Fifth Circuit U.S. Court of Appeals.
What’s the big idea?
The Supreme Court isn’t the predictable, partisan institution we think it is. It’s shaped as much by individual justices, internal dynamics, and institutional self-preservation as by ideology. To understand it, you must look past the left-right narrative and see the complexity underneath.
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1. Doppelgangers.
Brett Kavanaugh and Neil Gorsuch are as close to a twin study as the Supreme Court will ever have. They’ve led remarkably similar lives. They were both the sons of high-achieving mothers who had climbed the power structures in Washington, D.C., before there was even a women’s restroom in the Senate. They both went to the same high school—together. They worked as law clerks on the Supreme Court for the same justice, in the same term. The two spent a decade as circuit court judges, belonged to the Federalist Society, and were nominated to the Court within eighteen months of each other. They were both nominated by the same president with the seal of approval from the same conservative legal scholars.
But their jurisprudence is radically diverging. In 2025, Justices Kavanaugh and Gorsuch were on the same side in only 50 percent of closely divided cases. Justice Kavanaugh was more likely to agree with Justices Kagan, Sotomayor, Thomas, Alito, Barrett, and the chief than with Justice Gorsuch. Only Justice Jackson ranked lower.
They almost seem to repel each other. Trump v. Illinois—stopping Trump from federalizing the national guard in Illinois—was decided 6-3. Kavanaugh voted against the president, and Gorsuch voted in favor. But what’s fascinating is that they switched sides in Learning Resources—also decided 6-3, striking down President Trump’s worldwide tariffs. Now, Gorsuch voted against the president, and Kavanaugh voted in favor. Every other justice stayed put.
Since joining the Court, Justice Kavanaugh has been in the majority more often than any justice since at least 1953. To understand the Court, you have to understand Kavanaugh. And to understand Kavanaugh, you have to understand his mirror image, Justice Gorsuch.
2. Large language model overlords aren’t taking my job anytime soon.
Large language models are notoriously bad at predicting the outcomes of Supreme Court decisions. I fed a popular AI model the briefs from each case in the 2024-2025 term. It predicted unanimous outcomes in 21 percent of cases and 6-3 outcomes in 42 percent. The reality was almost the opposite: 42 percent of the cases were unanimous, and 15 percent were 6-3. With any sort of political valence, the AI tended to assume the outcome would be 6–3 along ideological lines, even though that is one of the least likely outcomes.
“Large language models are notoriously bad at predicting the outcomes of Supreme Court decisions.”
Why are LLMs so bad at this? Because these systems reflect our own thoughts back to us. And, as one study found, the use of terms like Democrat, Republican, liberal, and conservative in media coverage of the Court tripled from 1980 to 2023. As the authors noted, “It would be nearly impossible to read contemporary articles about the Supreme Court without getting the impression that it is just as political as Congress and the presidency.” So, it’s no wonder AIs think every Supreme Court case will be 6–3. It’s how so many of our pundits and news feeds think, too.
3. If you give a conservative a cookie, he’s going to want to overturn gay marriage.
After 40 years and so many false starts (O’Connor, Souter, Kennedy), conservatives finally got the Court they wanted. Or did they? On the one hand, it’s easy to see the last several terms as the apotheosis of the conservative legal movement: on guns, abortion, religious liberty, affirmative action, and voting rights. But there’s something odd going on under the surface. A “we will go here but no further” is hidden in many of the opinions from the high institutionalists—Roberts, Kavanaugh, and Barrett.
All the while, conservative litigators are acting like the mouse that got the cookie. Now they’d like a glass of warm milk and maybe a straw. But what conservatives have seen as a good start may in fact be the end of the road. How do we know conservatives have some bumpy roads ahead? Just look at which circuits the Court is taking cases from and which of those circuits are getting reversed.
Remember: When it comes to predicting the outcome of any given case the Supreme Court has decided to review, it is more likely than not that they took the case because four justices thought it had been incorrectly decided below. In data terms, the Supreme Court historically is going to reverse whatever the lower court did about 70 percent of the time. Right off the bat, that gives you better betting odds than any table in Vegas.
“The Supreme Court historically is going to reverse whatever the lower court did about 70 percent of the time.”
The Court used to grant review in the largest number of cases from the very liberal Ninth Circuit. But not anymore. As Americans perceive the Court as becoming more conservative, it is the most conservative court—the Fifth Circuit—that is seeing many of its cases taken by the Court. In 2025, the Fifth Circuit had ten cases reversed—more than any other circuit. The liberal Ninth Circuit had only four cases flipped in 2025.
4. Ice luge tutorial.
At the end of the term, the justices’ clerks perform parodies of famous songs poking fun at the Court. All the justices attend the performances, but let’s just say some have a better sense of humor than others—so the clerks these days tend to go for more self-deprecating humor.
In 2025, “Defying Gravity” from Wicked was a hit when it became “Defending Companies” as clerks pondered what they’ll be doing in big law after they leave the Court. And then there was the hilarious Rule of Civil Procedure 60(b) skit about the grounds for relief from a final judgment. Maybe you had to be there.
Every Thursday, one chamber will host the clerk’s happy hour. Drinking games are prohibited these days. In the early days of the Roberts Court, one of the chambers procured an ice luge. If you aren’t familiar, neither was the chief justice when he heard about it days later. I like to imagine how awkward it must have been when he summoned one of his clerks to explain to him that an ice luge is a block of ice with a “track” that runs downhill. A clerk stands at the top of the luge with a bottle of liquor and pours. The clerk at the bottom gets a nice cold shot. An ice luge is not a tool amenable to appreciating fine spirits or sobriety. Once informed, the chief banned ice luges (again, can you imagine drafting that memo?).
“An ice luge is not a tool amenable to appreciating fine spirits or sobriety.”
But while hard liquor has technically been banned, anyone who needs a top off for their Coke knows which drawer to look in. (Just don’t tell the chief!)
5. What if Trump is Penguin to John Roberts’ Batman?
Back in 1941, Robert Jackson, famed attorney general, prosecutor at Nuremberg, and Supreme Court justice, wrote this about the institutional longevity of the Court:
In spite of its apparently vulnerable position, this Court has repeatedly overruled and thwarted both the Congress and the Executive. It has been in angry collision with the most dynamic and popular Presidents in our history. Jefferson retaliated with impeachment; Jackson denied its authority; Lincoln disobeyed a writ of the Chief Justice; Theodore Roosevelt, after his Presidency, proposed recall of judicial decisions; Wilson tried to liberalize its membership; and Franklin D. Roosevelt proposed to “reorganize.” It is surprising that it should not only survive but, with no might except the moral force of its judgments, should attain actual supremacy as a source of constitutional dogma.
But maybe it is not surprising at all. During President Washington’s tenure, the Court was a weak, barely noticeable branch. Our first Chief Justice Jay told John Adams that the Court lacked “the energy, weight and dignity which are essential to its affording due support to the national government.” Why? Because George Washington offered it nothing to counterbalance.
Chief Justice John Marshall was thrilled to have such useful adversaries as Presidents Jefferson and Jackson to prove the need for an independent judiciary in Marbury v. Madison and Worcester v Georgia. What if Trump—attacking the Court constantly—is doing Chief Justice Roberts a favor? Only time will tell.
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