Pertinacious Papist has re-posted an article by James Tillman titled "An Apology for the Confessional State" I post some of it here, but encourage you to read the entire article itself.
There are perhaps but two views of the state's purpose. In the traditional view, the state helps men to some definite idea of perfection by inculcating virtue in them through good laws; such an ideal has been advanced by Aristotle, Aquinas, and various Popes. In the classical liberal view, the state allows men to pursue whatever they want by protecting their freedom of action; such an idea has been advanced by Locke and various Protestants.
Rights are meant to delimit a sphere of action, within which each individual may do what he wants and the bordrs of which government is supposed to protect. Under such a system, government does not look to whether property is used for good or for ill; it simply protects one's right to have it and use it. Government does not look to whether free speech spreads lies or truth; it simply protects one's ability/right to speak. Deliberation regarding laws centers on how best to protect the various rights, not onl whether laws will help men be better men. Like that of the Wiccans, the classical liberal motto is "If it harm none, do what ye will."
In reality, however, such an idea of rights cannot ultimately be enforced without appealing to a specific standard of morality and thus without enforcing a specific standard of morality. To see why government cannot enforce rights without an appeal to morality, we must examine a few rights in the concrete.
When such rights are examined, we find quickly that they are not absolute. Freedom of speech infamously does not give one the right to yell "Fire!" in a crowded theatre. Neither does it give one the right to put a sign on one's lawn advocating the lynching of African-Americans. The right to freedom of speech is outweighed by the right to life. The majority of cases, however, are not so clear. Does freedom of speech permit me to sell books advocating a subversive and Communist political philosophy? Does it permit me to sell books on how to conduct a coup d'état? Does it permit one to put up billboards quoting the Levitical laws against sodomy? Such cases are not easy to decide and will require significant prudential deliberation regarding the goods to be gained and lost by each course of action. In each case the so-called "right" to freedom of speech is clearly not an absolute right; those who make decisions do not make them based upon clear and unambiguous laws, but upon prudential weighing of the various goods involved.
Similarly, the right to freedom of religion requires prudential decision-making. Some religions involve smoking marijuana; others involve polygamy; others involve the execution of those who decide to leave that religion and the establishment of a world-wide theocracy beneath religious law. Such religions may be offensive to Catholics, just as the Catholic religion is offensive to those who believe that it teaches people to hate homosexuals, that it represses man's natural instincts, that it advocates the subjugation of women, or that it leaves one ultimately loyal to a monarch in the Vatican rather than to the United States. When government decides what sort of religion to allow and to what extent to allow it, then it does not simply take into account the right to religious freedom; one also takes into account a host of other moral evaluations regarding the importance of various goods. Similar instances might be given as regards education, the right to private property, and so on and so forth.
[...] Inasmuch as the Republican -- or even the Democrat -- agenda agrees with the Catholic, to that extent they can be made temporary allies; but we must never mistake such an alliance for a friendship. There is no agenda for the Catholic but the Catholic agenda, which would require decades of unremitting effort for its realization and which would require men to transcend most of the issues currently dividing political parties. The Catholic agenda requires us to admit what the rest of society yet hypocritically denies -- that between rival moral theories there can be no peace.
Catacombs or Christendom? Society slides and wavers between the two; but there can be no third way.