On Tuesday, an outfit called the Council on Biblical Manhood and Womanhood issued, over the signatures of more than 150 evangelical leaders, the Nashville Statement -- a 14-article manifesto saying pretty much what you'd expect 150 evangelical leaders to say about marriage, sexuality, and gender identity.

As in Article One:

WE AFFIRM that God has designed marriage to be a covenantal, sexual, procreative, lifelong union of one man and one woman, as husband and wife, and is meant to signify the covenant love between Christ and his bride the church. WE DENY that God has designed marriage to be a homosexual, polygamous, or polyamorous relationship. We also deny that marriage is a mere human contract rather than a covenant made before God.

In my view, the Bible is rather less clear on manhood and womanhood than the confident assertions of the Nashville Statement suggest, there being at least four wives among the three Patriarchs in Genesis, to say nothing of the polygamous and polyamorous behavior of David and Solomon, or David's arguably homoerotic relationship with Jonathan.

But as a devotee of the Free Exercise Clause I say: Go for it, guys. If that old-time heteronormativity is the hill you want evangelical Christianity to die on, be my guest.

For we should be clear why this Statement is appearing now. The faithful are harkening unto what its Preamble identifies as the "secular spirit of the age."

Thus, according to a Pew report delivered earlier this summer, fully 35 percent of white evangelical Protestants now support same-sex marriage (up from 13 percent in 2001). The number is 47 percent when it comes to those under the age of 53.

Moreover, PRRI found this spring that just half of white evangelicals favor laws requiring transgender people to use bathrooms corresponding to their birth sex. Can acceptance of "transgenderism" be far behind?

No wonder the evangelical leaders have decided to draw lines in the sand.

To be fair, the Nashville Statement does in places tip its hat to the norms of 21st-century Western culture, which the Preamble denominates "increasingly post-Christian." It affirms that "people who experience sexual attraction for the same sex may live a rich and fruitful life" and that "those born with a physical disorder of sex development are created in the image of God and have dignity and worth equal to all other image-bearers."

But it's hard to square such assertions with its denial that "adopting a homosexual or transgender self-conception is consistent with God’s holy purposes in creation and redemption." So far as the Nashville Statement is concerned, God's holy purposes in creation and redemption boil down to body parts and procreation.