A thought-provoking article from Fr. John Zuhlsdorf:
Time and time again religious who pronounce themselves on social issues demonstrate that they think of nation-states, such as the USA, in religious terms. Nation-states are their communities writ large, in which everybody helps everybody else, and in which goods are distributed not on the basis of property rights, but instead, as in the Acts of the Apostles, “distribution is made to each according to his need” (Acts 4:35).
http://wdtprs.com/blog/2012/03/why-a-religious-model-for-the-state-is-not-good/