Brian Walsh of the Ethics & Public Policy Center's Religious Freedom project has an essay on Thomas Jefferson's commitment to the rights of conscience that perfectly demonstrates the limits of the neo-conservative worldview. Here is the key graph:
Why would a sophisticated thinker like Jefferson, with elaborate reasons buttressing his harsh critique of the Christian beliefs of his contemporaries, promote a position on religious freedom that orthodox believers of many faiths argue for today? Jefferson understood the power that the truth has to prevail in a free and open marketplace of ideas. He of course considered his own understanding of religion to be true, and thought that—if he was indeed correct—his views would eventually win out. Thus he wrote in a letter to a Unitarian minister that “if the freedom of religion, guaranteed to us by law in theory, can ever rise in practice under the overbearing inquisition of public opinion, truth will prevail over fanaticism.” He valued each person’s freedom to pursue and follow truth, and thought civil society would be able to embody greater truth and flourishing only through the free and peaceful exchange of ideas. Instead of opposing religious liberty, those who share Jefferson’s skepticism toward traditional religion thus have good reason to join him in advocating robust rights of free exercise.
See the problem? The "free and open marketplace" of ideas is only open to religious ideas that give freedom priority before truth, and which demand a kind of privatization of religion by relegating it out of the public, civil square. Certainly, only if one accepts the dualism of John Courtney Murray, rooted in Gelasian understandings of the relationship of church and state, does this free marketplace seem so free. Again, the neo-cons do not realize how far down the slope of secularization they already are.