"Essentially, Protestantism is nothing other than a generally applied papism. For in Protestantism, the fundamental principle of papism is brought to life by each man individually. After the example of the infallible man in Rome, each Protestant is a cloned infallible man, because he pretends to personal infallibility in matters of faith."
It is needless to explain, I trust, that the only despotism of the Pope consists in the fact that all Catholics believe that God will guard him from teaching falsehood to the Church on those special and rather rare occasions when he is appealed to to end a controversy with a finalstatement of faith. His ordinary pronouncements, though naturally received with profound respect, are not infallible. His private character depends on his own free will, like anybody else's. He can commit sins like anybody else; he must confess sins like anybody else; and his having been Pope is nothing to his salvation.
And he must obey the Magisterium as well as anyone else too.
For each Pope there was a Magisterium before he became Pope.
When Urban VIII condemned Heliocentrism, he obeyed the previous Magisterium./HGL