“From 2018-2020 there was a dramatic and strongly statistically significant spike in both partisan splits and partisan reversals — more in both categories than we observed in any other time period over 60 years,” Neal Devins and Allison Orr Larsen, law professors at William & Mary, wrote in the study, called “Weaponizing En Banc,” to be published in The New York University Law Review.

By partisan splits, they meant full-court panels in which the judges appointed by presidents of one party almost perfectly diverged from those appointed by ones of the other party. Partisan reversals were what the term implies: ones in which an en banc majority dominated by appointees of presidents of the party in control of the court, over the dissents of most appointees of the minority party, overturned a three-judge panel dominated by appointees of the minority party.

Here is an example of both things.