Using a simple data matrix, uberpollster Nate Silver has predicted in what order gay marriage will be permitted on a state-by-state basis.
Nate Silver at Five Thirty Eight Politics analyzed each state's record of gay marriage bans, religiosity according to a 2008 Gallup survey, and number of evangelical residents to determine how long it would be before gay marriage was legalized. The results were not as predictable as you might think.
Noting the steady decline in religious conviction alone, Proposition 8 could mark one of the last wholesale gay marriage bans to ever be amended to a state's constitution. Of course, legalization is wholly dependent on the sociopolitical climate. If evangelicals see a renaissance, gay marriage proponents could see their prospects dwindle.
The rankings of the states by year they will likely reject marriage bans: