The Idaho legislators have passed a Constitutional Amendment to ban gay marriage, so now it will go to the voters. I suppose that conservative Idaho will pass this, though you never know.
Opponents of the amendment ought to shift the debate. Too many people will support the amendment if they just think it only affects homosexuals. I'd try to tie the inherent bigotry of the effort to the image of our state as bigots.
The counter argument would be, we don't want to pass the amendment because we already are perceived as racists and bigots. Passing it will just reinforce that view. Since we already have a law against gay marriage, the amendment is unnecessary anyway, so why tarnish our state's image and scare off tourists and their money. Always find a money angle.