Perhaps you can show whether, how, and to what degree a decree of a pastoral council corrected the previous magisterium, particularly in light of Cardinal Ratzinger’s statement:

“The Second Vatican Council has not been treated as a part of the entire living Tradition of the Church, but as an end of Tradition, a new start from zero. The truth is that this particular Council defined no dogma at all, and deliberately chose to remain on a modest level, as a merely pastoral council; and yet many treat it as though it had made itself into a sort of superdogma which takes away the importance of all the rest.” — Cardinal Joseph Ratzinger, “Address to the Bishops of Chile,” (13 July 1988). Online; available from: http://www.vancouvervtms.com/wd/TradLatinMasses/Commentary/Cardinal%20Ratzinger%27s%20Address%20to%20Bishops%20of%20Chile.htm

And then there’s notification appended to Lumen Gentium. During the course of the Council, the Theological Commission published a Declaration dated March 6, 1964. The text was subsequently inserted into an official series of Notificationes appended to LG by Archbishop Pericle Felici, Secretery General to the Council. It therefore represents the authority of the Council itself in the matter:

“Taking conciliar custom into consideration and also the pastoral purpose of the present Council, the sacred Council defines as binding on the Church only those things in matters of faith and morals which it shall openly declare to be binding. The rest of the things which the sacred Council sets forth, inasmuch as they are the teaching of the Church’s supreme magisterium, ought to be accepted and embraced by each and every one of Christ’s faithful according to the mind of the sacred Council. The mind of the Council becomes known either from the matter treated or from its manner of speaking, in accordance with the norms of theological interpretation.”

29 Q. But if a man through no fault of his own is outside the Church, can he be saved?
A. If he is outside the Church through no fault of his, that is, if he is in good faith, and if he has received Baptism, or at least has the implicit desire of Baptism; and if, moreover, he sincerely seeks the truth and does God’s will as best he can such a man is indeed separated from the body of the Church, but is united to the soul of the Church and consequently is on the way of salvation

Fr. Michael Mueller, writing in the 1880′s, called that proposition a heresy. Now, I don’t think anybody would call Pope Pius X a heretic. So, how do you address this passage of Pius X’s catechism?

The quickest thing to show them is the infallible definition of Pope Euguene IV from the Council of Florence, which does not admit of that interpretation:

http://catholicism.org/cantate-domino.html

Read No. 4: “4. Blasphemy, foul language, bathroom talk, and links to immoral web sites will not be allowed.”

If you look up “blasphemy,” you will find that affronts to Our Lord Jesus Christ are covered in it. Should you actually read our site’s content, you will find that your false inference — “He must not be important here” — is just that.

Vatican II teaches no such thing. It is conceivable that one might read that meaning into an ambiguous passage, but this would violate the “hermeneutic of continuity” the present Holy Father says must be applied to Vatican II. What the Magisterium has defined infallibly is binding dogma. Vatican II has not bound us to new dogma, and this is verified by Pope Benedict XVI. You must not stop going to Church. You must hold binding Church dogma and reject what contradicts it, leaving the judgment of Vatican II to the Supreme Pontiff — the only authority on earth who can judge it definitively.