This decision has many presuppositions. First it was necessary to give to the term “tradition” a definite sense. One now distinguished between ecclesiastical and apostolic tradition. The apostolic tradition is the old traditions which came into the Church through ways which are not given in the Bible. But the ecclesiastical tradition is the tradition about which the Pope has to decide, whenever it appears in Church history. This was the situation; the ecclesiastical tradition, which was the only living tradition, was identical with the papal decisions. This is the positive statement.
And now its negative side: The Jesuits more and more undercut all other authorities. In contrast to Thomas Aquinas they undercut conscience and made themselves the leaders of the consciences of the princes, and of the other people too, But their important role was that in this period of Reformation and Counter- Reformation, where the Jesuit order was born in Spain, most of the deciding political personalities had Jesuitic advisors around themselves who were leaders of their consciences. Now if you guide, the conscience of a prince, you can apply this guidance to all political decisions because in all of them some moral elements are included. And that is what the Jesuits did. They turned the consciences of the Catholic princes towards all the cruelties of the Counter-Reformation. So the conscience was no authority any more.
Also the authority of the bishops was undercut by the Jesuits. The episcopalian primacy in the Councils was undercut by Jesuitic interpretation. The Councils themselves and their decisions have to be confirmed by the Pope. This was the complete victory of the :Rope over the Councils. This was done in Trent. The Pope was accepted by the majority of the bishops in Trent as he who has to confirm the Council of Trent. This means that no council can have validity ever since, which is not confirmed by the Pope. Therefore the Pope is beyond criticism.