It’s hosted by the SSPX website, but don’t let that deter you. (I was checking their website for articles such as this, since no one else publishes them).
One thing that’s amazed me since studying _Casti Connubii_ the past few months is that the Pre-Vatican II popes and theologians are much more open and honest when discussing NFP than post-Vatican II ones.
Bai MacFarlane, a tragic example of John Paul II’s idealized view of the modern Catholic family, has said that JPII often comes off as too positive, ignoring the challenges of marriage. _Humanae Vitae_ talks in general social terms but really doesn’t get to the heart of the average couple. _Casti Connubii_ does, and this article by Fr. Hugh Calkins, O.S.M., does.
He is not being “anti-Rhythm,” per se. And he is not, strictly speaking, being “providentialist” (though he does condemn the exaggeration of “prudence” by many Catholics). But he *is* advocating the clear teaching of Rome at the time that selective abstinence was not to be publicly taught or advocated, but was to be cautiously suggested by confessors to individual couples. And while NFP is an option for those who may have “grave reason,” that does not mean every couple with “grave reason” is obligated to use it (as Fr. Calkins puts it, the Church “tolerates” NFP).