The case of Anacletus II vs Innocent II is not like what we have today. In that example, there were 2 different elections, by 2 different groups of Cardinals. I don't know how anyone can say that it is an example of "universal acceptance".
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Not a single Cardinal disputes the election of JPII or Benedict. (John XXIII, with the white smoke, and Francis, with Benedict's abdication are a different story).