Because unfortunately there is a long history of powerful Catholics carrying water for political figures ... Archbishop Spellman's complicity in Roosevelt's eugenic policies being a stand-out for me.
In the wake of the Notre Dame stealth conferences on birth control in the 60's, several prominent Catholics (having been thoroughly conditioned by "foundation" monies and following the lead of utterly compromised Notre Dame president Hesburgh) took the lead in facilitating the State's sanctioning and enforcing of artificial contraceptoin as population control policy by testifying to Congress that they had no right to "impose their beliefs" on others and "speaking for Catholics" would shut up and sit down as the State proceeded about its objectives.
This was in stark contrast to the first half of the century where Catholics were at the forefront of forestalling the State's incursions into population control and the deconstruction of morals.
And, unfortunately, it's these Catholics-in-name-only who served as a model for today's "I'm personally opposed, BUT ..." Republicans and conservatives who by their caving on their personal convictions, allow the State to run roughshod over the populace and impose its "values".
The State is people. If you are a person whose "personal values" comport with the objectives and means of the State, you are ALWAYS well within your rights to impose your views of abortion, pornography, "de facto" unions, homosexual marriage, sexual education, environmentalism, anti-tobacco, etc. etc. on EVERYONE using the brawn of the State who's only too happy to play Big Brother in this regard.
Only if you stand for truths and those enduring moral laws which derive from God and are exemplified in large part by the moral codes of every human civilization since the beginning of human history, are you required to leave your personal convictions at home and play an impotent hypocrite in the Public Square.
I am embarrassed by my ignorance, but could you elaborate? I knew eugenics was popular in the 30s and into the 40s, when the Nazis "gave it a bad name," but pretty much all I know about it I read in Chesterton's Eugenics and Other Evils. I did not know Roosevelt was into it. (Spellman, of course, is just full of surprises.)