Same sex marriage inevitable?

Demographic trends suggest that same sex marriage is unstoppable in the USA. Consider this analysis from statistician and blogger Nate Silver:

The Iowa Supreme Court ruled today that same-sex marriage is protected under that state’s constitution. As in California, there will of course be an effort to amend the state constitution to prohibit gay marriage. […]

Most likely, […] Iowans won’t vote on the issue until 2012. […]

The state has roughly average levels of religiosity, including a fair number of white evangelicals, and the model predicts that if Iowans voted on a marriage ban today, it would pass with 56.0 percent of the vote.

By 2012, however, the model projects a toss-up:  50.4 percent of Iowans voting to approve the ban, and 49.6 percent opposed. In 2013 and all subsequent years, the model thinks the marriage ban would fail.

If Silver’s analysis can be trusted — and he’s extremely good at this sort of thing — we would see a 5.6% swing (from 56.0% to 50.4%) in only three years. That’s staggering!

Silver doesn’t quite say so, but I deduce that his model is tracking a decrease in the “religiosity” of America with each passing year. Silver says there’s “a very strong correspondence between the religiosity of a state and its propensity to ban gay marriage”; and then he predicts “that by 2012, almost half of the 50 states would vote against a marriage ban.”

And even among white evangelicals, it seems to me that younger folks are not as invested in conservative mores:  I think they have a more laissez-faire attitude toward both gays and abortion.

If you’re an evangelical Christian, you’d better pray for revival. Or if you’re a Republican, for that matter — demographic trends strongly favour the Democrats.