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no ban on a married Catholic man (possibly a layman, a Latin Rite deacon, one of the already exceptional Latin Rite priests, or an Eastern Rite priest) being ordained Bishop of Rome after being elected by the College of CardinalsThat was the theme of the third "act" of one of my favorite novels, 1978's The Vicar of Christ by Walter F. Murphy.
Act 1: The protagonist — a young Catholic, son of a U.S. diplomat, and U.S. Marine Corps junior officer, is wounded at Iwo Jima in WWII. After becoming a law professor, he's recalled to active duty for the Korean War, where he's awarded the Medal of Honor for valor as a battalion commander in combat. (The author was himself a decorated Marine officer in Korea.)
Act 2: Years later, the protagonist is a longtime law school dean. He's appointed Chief Justice of the United States because of political deal-making between the President and a couple of different senators who have agendas.
Years after that, after a personal tragedy, the protagonist resigns and joins a monastery.
Act 3: Having been a monk for just a couple of years, the protagonist is elected pope by the College of Cardinals as a compromise candidate after a long deadlock between the two front-runners. He takes the name "Francis" (after Francis of Assisi) and immediately begins shaking things up both institutionally and doctrinally — to the displeasure of traditionalists.
https://en.wikipedia.org/wiki/The_Vicar_of_Christ