Although it doesn’t break much new ground, Russell Shorto’s profile of hard-core anti-gay-marriage activists in the Sunday New York Times is notable for getting to the very heart of the matter. Unlike many Americans who dislike the idea of gay marriage while generally accepting gays and lesbians as people with a right to follow their sexual orientation, the activists (typically conservative evangelicals) Shorto interviews oppose gay marriage precisely because they cannot accept the idea of homosexuality as a biologically determined orientation. Indeed, he says, they seem to understand that any chink in the argument that homosexual behavior is a “libertine lifestyle,” a mental illness, or a disease, will expose them to a terrible series of moral and even theological dilemmas:

For them, the issue isn’t one of civil rights, because the term implies something inherent in the individual — being black, say, or a woman — and they deny that homosexuality is inherent. It can’t be, because that would mean God had created some people who are damned from birth, morally blackened. This really is the inescapable root of the whole issue.

Indeed it is. Accepting the scientific evidence that homosexuality is biological would turn the religious argument on the subject upside down, since discrimination against people because of their God-given nature is defiance of God’s will rather than obedience. And the self-condemnation involved would be unavoidable, since they could not simply cite the marginal scattering of scriptural condemnations of homosexuality from the story of Sodom and Gomorrah to Paul; these authorities, after all, knew nothing about biology other than their own observations. In this light, the anti-gay “prophetic stance” of so many politically active conservative evangelicals is another spiritually dangerous submission of religious truth to cultural conservatism and partisan politics.And that’s why they can’t compromise: they’re out on a limb with their souls on the line, secular to the core but unable to see it.