Regardless of where you stand on the debate over marriage, I think you will find this National Review article by George Weigel to be a thought-provoking one. Here is a passage from the article:
New York State notwithstanding, the argument over marriage will and must continue, because it touches first principles of democratic governance -- and because resistance to the agenda of the gay-marriage lobby is a necessary act of resistance against the dictatorship of relativism, in which coercive state power is used to impose on all of society a relativistic ethic of personal willfulness. In conducting that argument in the months and years ahead, it would be helpful if the proponents of marriage rightly understood would challenge the usurpation by the proponents of gay marriage of the civil-rights trump card.