Some conservatives, such as Santorum and Bennett share a political philosophy that does not oppose government's intrusive interference in private behavior to regulate morality. I would argue, at some risk of giving offense, that these views reflect a growing tension in American 'conservatism' that has resulted from the great increase in Catholic political conservatism here.
While the Puritans certainly regulated private as well as public morality, there has been a strong move away from that view in Protestant thinking over the past 250 years. The general Anglo-American worldview based on Protestant roots is strongly Lockean and emphasizes individual liberty. While for most it doesn't extend to the sort of libertarian views you seem to have (and which I often, but not always, share), claims of privacy and individual liberty are not alien to those reared in this tradition. Separation of Church and State is a distinctly American Protestant notion.
The modern conservative Catholics, of the Santorum and Bennett stripe, and I would also include the odious Pat Buchanan, stem from the European Catholic conservative tradition of the Counterreformation, the Inquisition and the 19th century cri d' coeur of the papacy against the modern world and classical liberalism. On a fundamental level, those men really don't believe in a right of privacy (whether constitutionally grounded or grounded in some natural law theory) and don't really believe in the separation of church and state. The believe in compelling people to be good, rather than preaching at them to be good.
I don't mean to suggest that Catholicism is the problem, rather that there is a strain in Catholic thought that is manifesting itself and which is not good for the Republic.
Substitute any political/relegious sect in the above.
One need not be a statist to be a faithful Catholic.