Last Time Conservatives Dismissed Major Encyclical, It Ended Terribly | The New Republic
I found this article looking at the way Catholic conservatism evolved in the US over the 50's and 60's to be very interesting.
In short, the argument runs that the American conservative intellectual movement (gee, from the perspective of the early 21st century, that's a phrase that's hard to credit) had a strong Catholic component to it, largely from the Church's strong anti-communist stance. But it was those Catholic commentators who attacked a 1961 encyclical (which I must admit, I was not aware of) by Pope John XXIII which reaffirmed the church's support for the welfare state, help to the Third World, and a retreat from colonialism.
This was unintentionally the precedent for liberal Catholics rejecting Humanae Vitae seven years later, leading virtually all Catholics in the US to be "cafeteria Catholics."
Interesting theory, but in the case of countries outside of America, the Church's rejection of an easy to use method of contraception which did not interfere with actual pregnancy was alone enough to make Catholics selective in their attention to Papal teachings.
That said, it has always been clear that the current American alignment of libertarianism with conservative Catholicism is an aberration: yes, the Church was staunchly anti-Communist in the 20th century, but it was never against government's involvement by way of policy in reducing poverty and helping workers. Quite the contrary.
Similarly, it is no surprise that Pope Francis has endorsed government and international action on climate change. Good on him.