If I remember correctly, Pope Paul VI had issued a 1967 Progressio Populorum encyclical which encouraged those who favored using the then newly-introduced birth control pills.The word was passed on to just about every bishop and priest in the world. Thus the later Humanae Vitae was a huge setback for them and their agenda.
Progressio Populorum encouraged responsible parenthood. It did
not encourage use of the birth control pill. That might have been the erroneous “wishful thinking” of many of the ignorant Catholics who read the “sound bites” in the newspapers about this encyclical, but that false understanding had little to do with what was said by Paul VI in the the encyclical itself.
According to the
1959 moral theology textbook by John C. Ford, S.J., and Gerard Kelly, S.J.,
Contemporary Moral Theology Vol. 1: “
It is hardly conceivable that the papal teaching on such things as divorce, contraception, the direct killing of the innocent…is anything short of infallible” (p.22).
According to John T. Noonan’s
1965 publication, *Contraception - A History of its Treatment by the Catholic Theolgians and Canonists: *"***Never had it been admitted by a Catholic theologian that complete sexual intercourse might be had in which by deliberation, procreation was excluded." ***(*p.*438).
According to Felix Cappelo, S.J.'s
1933 and
1961 edition of *De Matrimonio, *n. 816, speaking of the teaching of
Casti Connubii on the immorality of contraception, he says, “***These very solemn words,utterin ‘in signum legationis divinae,’ obviously are an expression of infallible teaching authority, that is, a definition *
ex cathedra.”
According to Arthur Vermeersch, S.J., in his
1931 commentary on
Casti Connubii, he says that “
the pope wished to put the stamp of his own infallible teaching authority on the traditional teaching of the Church” [cited by Ford,
Contemporary Moral Theology, Vol II (1964), *p.263-264]
According to A. Piscetta, S.S., and A Gennaro, S.S., in their seventh volume of
Elementa theologia moralis published in
1944, they
agree with Vermeersch above on the infallible teaching of Casti Connubii on the matter.
According to Francis Ter Haar, C.SS.R., in his
1939 text
Casus conscientiae, II. De praecipuis hujus aetatis vitiis eorumque remediis, n. 136, speaking of the passage against contraception in Casti Connubii, ""
this passage of the encyclical, contains a definition by the Roman Pontiff speaking ‘ex cathedra’.
According to Andre’ Snoeck, S.J., in his article"Fecondation inhibee et morale catholique," *Nouvelle revue theologique *75 (
1953), 690-702, at p. 700: “
the common opinion in the Church judges that we are here ocnfronted with an irrevocable condemnation of conjugal onanism.”
According to John Ford, S.J. and Gerard Kelly, S.J., in their text
Contemporary Moral Theology, Vol II - Marriage Questions, published in
1964, “
in condemning contraception as intrinsically and gravely immoral, Pius XI was clearly and solemnly declaring at ruth already infallibly tuaght by the universal Church… the main point is to insist on the substantial immutability of the Catholic doctrine on contraception**.” (p.271)
Consequently, according to Catholic moral theology texts of the 30s, 40s, 50s and early 60s,
Casti Connubii’s teaching against contraception was unanimously considered inreformable teaching of the Church. If there were some “wishful thinkers” that thought this immutable teaching could be changed by Paul VI, either they clung to an ignorant view or a professed a dishonest view of Catholic moral theology.
i’m subscribed to this thread so i don’t care if it takes weeks, i’ll get an update. i can wait, and i’m sure i’ll be waiting a while. 
