Not that this hasn’t been touched on before, but let’s go for it again:

Religion must be in politics.

Let’s start by acknowledging two facts.  First, that religion has persisted throughout human history.  Second, that laws are essentially morally based, and religion has always been about morality.

Now, why might a person want to excise religion from politics?

Reasons that leap to mind include:  Bias against religion, frustration at the influence of religion in politics, or else some legitimate case against the role of religion in politics.  The third, of course, assumes the first two are illegitimate.  Mere bigotry in the first case, sour grapes in the second.

What legitimate reason might there be, to disallow religion to influence politics?  Or else, on what good and high ground ought religious people to surrender their political influence?

I honestly cannot imagine any, except that some religion were to become so powerful yet so contrary to nature that it would actually be harmful to the populace.  However, history shows that this is more often the role of ideology than religion; in either case, dominion over that society does not last forever.

Much as I believe in representing my opponents in the best possible light, let us not do all of their work for them.  Rather, what is the positive case?  Why should religion be in politics?

Because it cannot be otherwise.

Consider, first of all, what governance is:  The provision of due rights and liberties, at the cost of civic duty and fealty to the state.  Politics, then, is simply the form that governance takes, including the rise and fall of those in power.

What is religion?  I might begin to define it as a system of belief regarding the foundation of reality.*  For our present purposes, this includes the notion of value and the way we determine whether a thing is good or ill.

Now, what is a right except that to which a person is entitled?

Is a person entitled to freedom of speech?  To security of his person?  To financial support no matter what his contribution to society has been?

We don’t need to answer these questions here.  We have only to note that, to answer them, one needs to have some concept of the value of a human being (call this “dignity”), and what means provide for the satisfaction of that dignity.  In other words, if we do not satisfy the dignity of our human citizens, we fail as a government.

How would you, dear reader, begin to answer this question?  What is the value of a human being?  What is human dignity?  How do we satisfy the demands of that dignity?

These are metaphysical questions.  There is no experiment which gives us the results we need to answer such questions.  As such, they make contact with the foundation of reality, which we have, historically, struggled to comprehend.

One does not have to be religious in order to venture a guess.  Be assured, however, that religion most certainly does offer answers to such questions, and always has.

Religion is not some foreign object, not some inhuman influence within human affairs.  It is a collective, enduring, thorough-going human endeavor.  Subject it to criticism if you like – if you will likewise endure scrutiny yourself – but do not disqualify it out-of-hand, lest you expose your barbarism.

Are your answers better than those of a religion?  Demonstrate it.  Otherwise, do not begrudge a person’s sincerely held beliefs.  Are yours objectively conclusive?  Can it be that only a fool denies what you assert?

Expel religion at your peril, then, for you will likely expel the religious as well.  Imagine, in an exercise belying your own foolishness, that they are no good anyhow.

Behold:  It is the religious who often survive in continuity, and who go on to establish new societies and remake old ones.

*Usually in a specific narrative form.  An ideology might take a narrative form, but the characters are often generalized or symbolic.  A religion concerns specific characters, taken to have acted within human history, and heeds the consequences of that story on the human race.