In the article I compare the Texas Supreme Court (the "SCOTX") and the U.S. Supreme Court (the "SCOTUS") and then ask the question reflected in the title, as follows:
"A comparison of the two courts shows that the number of nine seats is one of the fundamental ways in which the two courts are alike. The other two similarities are that each is created in organic law—the constitution—of the respective government—federal or state—of which each is a component and that each is the court of last resort, or apex, of the judicial branch of its respective government and accompanying legal system. Profound differences also obtain, of course. The SCOTUS is staffed by justices appointed by the President, and those justices enjoy lifetime tenure and protection against salary reduction during “good Behaviour." SCOTUS justices exit the bench only by death, resignation, or—since 1937—retirement. In contrast, the SCOTX is composed of justices who have won statewide election to serve fixed terms of only six years, on a staggered basis. The Texas justices thus serve at the pleasure of any majority of voters in an ongoing series of elections. Moreover, SCOTX justices have an age limitation of, more or less, 75 years; and they are not protected against salary reductions by the Legislature. Moreover, while the number of nine justices is legislatively determined for the SCOTUS, it is constitutionally established for the SCOTX. To change the number of justices, an appropriate vote is required—by very different voters: by Members of Congress and Senators voting to revise the federal Judicial Code for the SCOTUS and by a statewide vote of Texas citizens in a constitutional-amendment election for the SCOTX. And while no SCOTUS justice has ever left the bench to run subsequently for office in the executive or legislative branches, the SCOTX is a springboard for election to such other offices. With that comparison as background, consider now that first one of the three basic similarities of the two supreme courts—that is, both courts have the same number of justices, nine. The number of nine justices composing the SCOTUS has been fixed for a century and a half, since Congress enacted the Judiciary Act of 1869 in the aftermath of the Civil War; as noted, that number is 'carved in stone' as a result of the 1937 crisis. But the number of nine justices staffing the SCOTX is of much more recent vintage, dating from the adoption of a state constitutional amendment only 73 years ago, in 1945. So, a pertinent question for Texas legal history is why and how did nine become the number of justices for Texas’s highest civil court,13 the SCOTX, mirroring that of the SCOTUS?"
My article posits the answer to that question.....see the article here: https://www.yourhonor.com/web/images/pdfs/IC/2010s/IC_SUMMER_2018/24/