Gay marriage bans to fall nationwide in next 15 years?

So says the model proposed by Nate Silver at Fivethirtyeight.com. This presupposes that each state will visit (or revisit) the issue.

Check it out...it's worthwhile. The gist is this:

Unsurprisingly, there is a very strong correspondence between the religiosity of a state and its propensity to ban gay marriage, with a particular "bonus" effect depending on the number of white evangelicals in the state.

Marriage bans, however, are losing ground at a rate of slightly less than 2 points per year. So, for example, we'd project that a state in which a marriage ban passed with 60 percent of the vote last year would only have 58 percent of its voters approve the ban this year.

All of the other variables that I looked at -- race, education levels, party registration, etc. -- either did not appear to matter at all, or became redundant once we accounted for religiosity. Nor does it appear to make a significant difference whether the ban affected marriage only, or both marriage and civil unions.

For Iowa, Silver predicts that a constitutional ban on gay marriage would fail by 2013:

[T]he 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.

Even Mississippi would swing to the anti-ban column by 2024. Yes, Mississippi.

The Democratic Strategist provides more context:

What seems to have happened in the last few years, in Iowa as elsewhere, is that the question for politically and ideologically moderate voters on same-sex marriage has changed from "Why?" to "Why Not?" And that change in turn almost certainly reflects the lack of impact--other than images of smiling, happy couples--in states that have already legalized gay and lesbian marriages.

And The Nation weighs in as well, noting that by the time this issue makes it to the ballot (if it does)

the vote will take place after Iowans have witnessed 5-6 years of ho-hum same-sex nuptials of which the most radical, earth-shaking element is that one of the grooms is a 50-year old church organist named Otter Dreaming (one of the named appellees in the Iowa decision).

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One thing to note briefly here is the positively Midwestern sturdiness of the Iowa Constitution and political system, which makes sure that impeachment and Constitutional amendments go through the democratic process. California: take note!