The error of collegiality is important to understand as it forms an integral part of the post-conciliar crisis. Here Fr. Wrighton gives an excellent explanation of collegiality's origins, its introduction by the liberals at Vatican II and current implementation.
Collegiality: it's one of the keynote errors of the Second Vatican Council which Archbishop Lefebvre strenously fought against and which the SSPX has continued to oppose. However, the beginnings of this error concerning the hierarchy of authority in the Church started long before the dawn of the 20th century.
Fr. Basil Wrighton traces in his 2-part article (first published in 1984) the history of Collegiality: Error of Vatican II, particularly of the machinations used to implement it during the Council and how a last-second intervention with Pope Paul VI avoided an even worse catastrophe. He then demonstrates the implementation of this error that seeks to democratize the Church (particularly the papacy) during the post-conciliar period.