Why Maine voters repealed a gay marriage law Tuesday when polling favored backers continues to baffle analysts. Several theories have been offered.

Gay marriage proponents have been hit hard by the defeat, which came on the first anniversary of another trouncing: California's voter-approved gay marriage ban, Proposition 8. In both fights, gay activists hoped a liberal electorate would favor gay marriage rights.

The long-held notion of a “Bradley effect” for gay marriage, where people are reluctant to share their true feelings on a social issue, is the most frequently cited reason for why pollsters got it wrong.

By Thursday, conservative monthly The American Spectator was among the many discussing the possibility. In a blog post titled Gay Marriage “Bradley Effect,” W. James Angle, III argued that the phenomenon “cuts both ways.”

“It suggests that overall public opposition to same-sex marriage may be understated in national polls, raising questions of how much the recent shifts reflect rising support or just the public's sense of what the socially acceptable position is.”

“On the other hand, if [opposition to gay marriage] is now something people are afraid to say to strangers, that doesn't bode well for traditional marriage's long-term prospects. It suggests that the bandwagon effect could work, putting opposition to same-sex marriage in the closet or reducing it to the opinion that dare not speak its name,” he said.

Statistician Nate Silver, who gave Question 1 a 70% chance of failing, agreed that polling could be skewed by a “Bradley effect,” but he also said there could a number of other reasons, including the geography of a state.

“The results showed a very strong urban-rural divide, with the initiative being rejected by a margin of about 2:1 in Portland but racking up big margins in smaller towns and rural areas, especially in the north of the state,” he said in a blog post at fivethirtyeight.com.

Results from Proposition 8 last year were similar, with coastal city dwellers rejecting the gay marriage ban, while inland rural folks voted overwhelmingly in favor of Proposition 8.

Gay activists in California are already tackling this theory. Meet in the Middle 4 Equality was a gay marriage rally held in rural Fresno in May. Organizer Robin McGehee likened the rally to moving the fight “behind enemy lines.” A strategy activists will inevitably need to repeat if Proposition 8 is to be repealed.

And if Maine stages a second gay marriage referendum.