How should Catholic Social Thought be employed in policy debates?

My "Catholic Social Thought and the Law" student, Joe Callaghan, shares these thoughts:

Does Catholic social teaching offer ideas and values that might find broad-based acceptance? Yes. And no. Yes in that the final product of Catholic social teaching is often appealing to adherents to other value systems. No in that, to a non-Catholic, to theoretically underpin a policy on ideas like “God’s love” or “Truth” or “human dignity” or “solidarity” rings a bit hollow. Take, for instance, the Universal Declaration of Human Rights. Everyone was able to agree on the fundamental rights of human beings, but I cannot imagine that the process through which the Canadian delegate and the delegate from the USSR arrived at provision of time off from work for periodic holidays and leisure time was at all comparable. At some point (nicely illustrated in Jacques Maritain’s description of the problem posed by the rate at which the commons of society is being filled with rights), some “old right” will come into direct conflict, direct as in litigation-worthy, with a “new right” and lawmakers will have to articulate why the new right is superior or more compelling or more aligned with the statutory scheme or more reconcilable with the Constitution than the “old right.” Eventually, we’ll reach a terminal arrangement of rights and this town will be too small for the both of the two supposedly-absolute rights. What happens then? What happens when Catholic social teaching is the sole distinguishing consideration weighing in favor of one of the rights and you are advocating for that right among non-Catholics? Can you invoke objective Truth as revealed in Creation? Can you cite to the perfect model of love in the Trinity? Is it disingenuous to form your opinion on a legal matter based on your reflection on Catholic social doctrine and then to present an argument based on stare decisis or compelling state interest or some other principle? It seems like I’d have a tough time arguing human dignity by virtue of the imago dei when I know that no one else in the room buys it. And it seems less than honest to argue something other than my true conviction. So, I think that the policy ends reached by Catholic social teaching surely offer ideas and values that might find broad-based acceptance. But, I’m not sure that a full explanation of the reasons that we arrived at certain policy ends wouldn’t convince would-be supporters to turn and run the other way.