There are some prominent areas of irreconcilable disagreement, such as the issue of abortion. As Prothero eagerly highlights, Ayn Rand claimed the unborn have no rights to recognize. Nevertheless, such differences stand out as exceptions among shared goals. Also noteworthy, the disagreement over abortion pivots on the interpretation of individual rights rather than recognition of those rights.
Bottom line: the Left has much to lose from a coalition between Christians and Objectivists. An alliance of secular and religious activists in support of individual rights would stabilize one of the major fault lines commonly exploited to disrupt Republican unity.
That said, we would be remiss without acknowledging professing Christian theocrats who have as much to lose from a mainstreaming of Objectivist principles as the Left does. If you expect government to compel Christian living, to punish sin and subsidize faith, then you prove as statist as any leftist. Recall that the progressive era in the late 19th and early 20th centuries birthed the nationwide prohibition of alcohol, advocated primarily by Christian moralists. In so doing, those Christians broke from their forebears who sought no such control over individual lives, yet were just as religious.
It is one thing to preach the reality of sin, and quite another to claim an earthly authority to codify religious judgments into civil law. While the often abused phrase “separation of church and state” is found nowhere in the Constitution, the guarantee of religious freedom requires compartmentalizing civil and ecclesiastical authority. Religion cannot properly be the basis for civil law.
Whether we believe our nature is God-given or merely “a metaphysical given,” our rights are derived from that nature. We shall either recognize and protect them, or sanction their violation. As God knew from eternity past, the endowment of rights enables sin. If He, in his infinite wisdom, cannot be properly credited with sin for enabling it through creation, surely we cannot be properly credited with sin for enabling it through legislation. God made us free and has dealt with our sin in his way on his timetable. It is not for us to feebly add to his finished work through state-enforced legalism. God’s got sin covered. When dealing with each other here on Earth, let reason prevail.