Feb. 17 (Bloomberg) -- Here’s a modest proposal: Let’s tax sex and use the proceeds to fund birth control for women whose health plans don’t cover it. Surely this compromise would resolve the controversy over contraceptives and religious organizations. All women would have access to contraception, and religious objectors wouldn’t have to pay a penny.

Before you start laughing, consider the policy arguments. It’s heterosexual sex that creates the medical problem contraception is intended to avert, so we would be aligning the incentives properly. Moreover, by all accounts there is plenty of sex going on in America, so the tax would generate a great deal of money. (If 200 million sexually active citizens have sex twice a month, a $2 fee would amount to about $10 billion a year. Of course, we would have to rely on self-reporting, but that’s a separate issue.)

True, the people actually engaging in sex (as well as many others who wish they were) might object that the sex tax burdens a fundamental right. They would be entirely correct. But so what? The Constitution (which doesn’t mention sex) is after all a living document, which must be reinterpreted to meet the needs of the era. And the basic need of this era, it seems, is contraception for all. Thus the claim of right must yield.

Fundamental Rights

This is basically the position of those who think we should ignore the objections of the Catholic bishops and others to the new Health and Human Services rule (and it is a final rule, not a proposed rule) requiring employers to provide health insurance that covers a variety of forms of contraception. The Catholic bishops and other protesters are making precisely the same argument as would arise against my proposal for a sex tax: that it violates a fundamental right. And, unlike the right to sex (which I take it most of us hold dear) the right to religion is actually mentioned in the Constitution.

The initial HHS rule required all employers, subject to a religious exemption drawn with contemptuous narrowness, to provide health insurance policies that included various forms of contraception. After protests, the administration rewrote the rule in a way that makes no difference whatsoever. Now the rule requires that the insurer cover contraception, but the employer evidently need not tell the employee this -- the insurance company will explain it instead -- and then the employee gets the contraceptives anyway, under the plan purchased by the employer.

The Catholic bishops and their supporters argue that the state cannot force them to pay, directly or indirectly, for medical treatments or procedures that they oppose on religious grounds. This, say the bishops, violates the Free Exercise Clause of the First Amendment. The administration, although willing for political reasons to seek some middle ground, plainly disagrees. The case for requiring health insurance to pay for contraception is a strong one, and I don’t share the bishops’ theological objections. But as a matter of religious freedom, an issue about which I care passionately, I am quite sure they are right.

What’s troubling about the controversy is not that HHS is wrong -- every agency, alas, gets the Constitution wrong now and then -- but the way that it is wrong. Fundamentally, the HHS rules misconceive the separation of church and state; and getting the separation right is one of the basic duties of government.

The separation of church and state is best understood as a compromise between two great centers of authority. The term appears nowhere in the Constitution, and Justice Stanley Reed was quite correct when he warned in 1948 that “a rule of law should not be drawn from a figure of speech.” Yet the ideal of separation has an unquestioned resonance in American public life, and has had since before the nation was born.

Wall of Separation

Although the provenance of the wall of separation stretches well back in Protestant theology, it was popularized in the New World by the Baptist preacher Roger Williams, the founder of Rhode Island, who wrote of the garden and the wilderness, separated by a high hedge wall. The garden was the place where God’s people worked together to understand what the Lord required of them. They were protected from the encroaching wilderness by that hedge wall.

That is the point: The wall protects the garden from the wilderness, not the other way around. With time, it is true, we have come to see the wall constraining church as well as state, and we as a nation are better for that understanding. But we should not, in our historical confusion, imagine that the wall was ever meant to hold back only the church, with the state free to breach at whim.

The wall of separation is metaphorical. It has no clear demarcation. For that reason, both parties to the compact do well to steer very clear of anything close to a confrontation. That is why the people of the garden should always be wary in lending support, on theological grounds, to any particular piece of legislation, for in doing so they turn theological claims of justice into opportunities for state coercion -- a temptation all too often irresistible to religious right and left alike.

But the present crisis has not arisen because the bishops have overreached. They are not trying to forbid contraception to those beyond their jurisdiction. They simply want to be free to engage in the charitable acts their faith requires -- including such acts as operating hospitals -- without being forced to pay for procedures to which they have strong and long-standing theological objections.

One might respond that operating a hospital is different from holding a belief, and that the bishops are perfectly well protected as long as they are merely preaching. The obvious rejoinder is that HHS, too, could call upon employers to provide contraception without forcing them to do so, and so stay safely on its side of the wall of separation, for state as well as church must respect the wall.

Words Versus Action

If the fact that allows the state to regulate is that the bishops are acting rather than merely preaching, let us consider the sex tax. To argue that religion is just belief is like arguing that sex is just desire. If the state can ensnare the religionists in its regulatory web once they cross the line from words to action, surely the state should be able to regulate those who choose to engage in sex rather than just dream about it.

What religious freedom requires is that the state remain on its side of the wall, absent the most compelling of justifications for breach -- punishing violent crime, for example. This principle should be honored across lines of party and ideology.

The Constitution, with all those pesky rights and cumbersome processes, often gets in the way of government action. But that is exactly what the document is for. It slows us down, forces us to rethink, forbids us to place our agenda above its guarantees.

You can think the HHS rule a wise one. You can think the protests misguided. You can believe that the government should indeed be able to command religious organizations to pay for medical procedures for their employees, even when the religion objects. You can believe all of that, and be a perfectly civic-minded individual. What you cannot do is to believe all of that, and also support the separation of church and state.

That is what worries me: On the evidence of this rule, it is hard not to conclude that those who have written it do not, fundamentally, understand the compromise on which the religion clause of the First Amendment rests. If HHS regulators believe that the wall of separation imprisons the church but allows the state to decide where the boundaries lie, then negotiation would be fruitless. So fundamental a misunderstanding of the constitutional order should be corrected, and swiftly, by wiser heads in the administration.

(Stephen L. Carter is a Bloomberg View columnist and a professor of law at Yale University. He is the author of “The Violence of Peace: America’s Wars in the Age of Obama,” and his next novel, “The Impeachment of Abraham Lincoln,” will be published in July. The opinions expressed are his own.)

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To contact the writer of this article: Stephen Carter at stephen.carter@yale.edu.

To contact the editor responsible for this article: Michael Newman at mnewman43@bloomberg.net.