Did Christianity Set Conditions for Marriage Equality?

Did a uniquely American version of 18th-century Christianity pave the way for same-sex marriage today? That's the claim Damon Linker makes in The Week.

Linker notes that most Christian denominations remain officially opposed to same-sex marriage but then highlights the radical equality that early American Christians favored:

The ultimate source of the democratic revolution -- the motor behind its inexorable unfolding -- is the figure of Jesus Christ, who taught the equal dignity of all persons, and declared in the Sermon on the Mount that the last shall be first and the first shall be last, and that the meek shall inherit the earth.

These are among the most subversive teachings ever uttered -- and according to Tocqueville, Western civilization has been working out their logic for the better part of two millennia, as political communities have applied Christ's egalitarian teachings in stricter and stricter terms.

He then says that American Christianity is providing a basis for support of same-sex marriage:

The same terror grips opponents of gay marriage today, as the Christian principle of equality overturns and transforms the Christian tradition's historic understanding of what a marital partnership is and can be. In this sense, at least, opposition to gay marriage parallels an earlier generation's opposition to interracial marriage. In both cases, the opponents of change are attempting to stand against the march of equality. In both cases, the opponents will fail.

He concludes:

Equality always wins. And equality became the lodestar of Western culture thanks to Christianity.

So, do you think Christianity in America has helped or hurt marriage equality efforts?