Law — enforced governmental policy — is properly an attempt to implement a universal system of ethics as a set of inviolable social rules via a central organizational authority. Because this is a real, concrete implementation of a system of ethics, law must employ an empirically, logically valid, demonstrably reasoned system of ethics as its basis. Mere moralizing cannot fit these requirements. A statement of metaphysical belief is not sufficient to justify the use of a given system of ethics as the basis for a system of jurisprudence. Metaphysical belief systems cannot be proven and, in fact, direct evidence cannot be provided for them. There is no way to either prove or disprove the existence of Allah, Zeus, Gaea, or Brahman.
This being the case, there is a concrete, ethical requirement to avoid condemning others for believing in Jesus Christ and adhering to the associated morality simply because of one’s own belief in Brahman, or vice versa, at least on the physical plane. Concrete circumstances call for concrete ethics. If you wish to hold someone in moral contempt for failing to believe the “right” things or for adhering to the “wrong” morality, you are of course quite free to do so — but visiting punishment upon them in this material realm for such differences of opinion is without provable justification. It is even morally wrong, according to most (if not all) of the most common belief systems, though that is immaterial to this discussion.
While empirical observation and logical reasoning are by no means without their fundamental uncertainties, they are the necessary basis for any attempt at a universal system of ethics. A universal system of ethics, in turn, is the necessary basis for a universal system of law, and that system of ethics must be based upon nothing more than empirical observation and logic — because that’s the closest we’ll get to being sure of anything. After all, if empirical observation and logic cannot be trusted to any degree, the whole question of morality and ethics, and of the proper ordering of society, is moot. It’s really that simple.
It is for this reason that we cannot base law upon religious doctrines, individual whims of dictators and kings, or mere majority rule, except insofar as such sources of law might coincide with empirical and logical reasoning or, perhaps, even be mandated by empirical observation and logic. Thus, government in the United States was designed to incorporate checks and balances, to limit the ability of democratic process to easily and radically alter the form government takes, and to strictly separate church and state. Government is, at its most fundamental level, the implementation of law. It must be protected against the encroachment of influences on law that contradict ethics derived from empirical and logical reasoning. This was, in general, the intent of the “founding fathers” in their creation and ratification of first the Articles of Confederation, and later the Constitution of the United States of America. It fails only insofar as it was the product of decision by committee, and as it was written by men convinced of their own fallibility and the future goodness of humanity.
The first and most important matter for consideration when choosing whether to support or oppose a bill in front of the legislature should be a universal system of ethics derived from first principles via empirical observation and logic. The Bill of Rights serves as a reasonable guesstimation at the requirements of such a system of ethics as codified in law. Thus, when making such a decision of support or opposition, consider first whether it directly violates any part of any Amendment in the Bill of Rights: if so, reject it. Consider second whether it necessarily supports any Amendments in the Bill of Rights: if it does not, consider finally whether it contains any potential for abuse to violate any part of any Amendment in the Bill of Rights, and if so, reject it again. I speak here of the clear and obvious spirit of the Amendments that make up the Bill of Rights, and not of the lawyerly obfuscations and loophole exploitations that make up some nontrivial part of what passes for Constitutional law in many courtrooms today. Do not impose your expectations of what should have been meant in the Bill of Rights upon its phrasing: see these Amendments for what they truly are, and how they were intended.
Similarly, apply such thinking to consideration of candidates for political office. If they do not regard the Bill of Rights or (even better) a universal system of ethics predicated upon empirical observation and logic as the fundamental set of imperatives for their policies in office, do not vote for them. To do so is to condone all the abuses arising from their derivation of policy from inappropriate sources, such as a religion that disenfranchises millions of well-meaning, unintrusive, good-hearted American citizens who may be the best neighbors a person could have, if they’re not in jail.