Congress has provided that certain kinds of election law cases must be handled by 3-judge U.S. District Courts. That includes cases involving redistricting. In 2017, a lawsuit was filed in U.S. District Court in Sacramento over the huge population of California legislative districts. Citizens for Fair Representation v Padilla, e.d., 2:17cv-973. The U.S. District Court who received the case first granted a 3-judge court, but then a few weeks later she retracted it, and seemed to say in oral argument that the reason she retracted it was that the Chief Judge of the Ninth Circuit told her to retract it.
On August 3, the plaintiffs asked the U.S. Supreme Court to help them get their 3-judge court. The brief to the U.S. Supreme Court points out that the Chief Judge of the Ninth Circuit has never heard the case, and presumably has not even read the briefs. The request to the U.S. Supreme Court asks that Court to tell the U.S. District Court Judge that she is supposed to make her own independent decision about whether to convene a 3-judge court. Here is the filing in the U.S. Supreme Court. Thanks to Rick Hasen for the link. UPDATE: the case number in the U.S. Supreme Court is 18-123. Thanks to Thomas Jones for the number.