As the Supreme Court ponders arguments for and against the legalization of same-sex marriage, the justices inevitably wrestle with the legacy of Roe v. Wade. In retrospect, that landmark case, far from settling a contentious social argument, inflamed the situation. In the 40 years since abortion became a constitutional "right," those on either side of the debate have only hardened their stances rather than finding common ground. Indeed, just the other day, lawmakers in North Dakota passed legislation that would effectively outlaw abortion in the state, openly challenging established law and essentially defying the Supreme Court. The current justices are presumably leery about the prospect of launching another 40 year crusade, this time against gay marriage.
I don't think the Court needs to worry about that much. Certainly there are people who feel passionately that marriage is a strictly heterosexual institution, but I doubt that a decision in favor of same-sex marriage would lead to the sort of never-ending, take-no-prisoners battle that commenced in the wake of Roe v. Wade. For one thing, even if one truly feels that same-sex marriage is wrong, it is, at worst, a victimless "crime": Scaremongers howl that gay marriage somehow "threatens" the institution of marriage yet cannot offer any plausible evidence for their claim. As far as I can see, their arguments boil down to linguistic tautology: Changing the definition of marriage harms marriage because it changes the way "marriage" is defined. Unless a change of definition is inherently harmful, though, this argument is meaningless.
Definitions change constantly, I suspect in the future we will lament the changed definition of marriage about as much as, say, Clarence Thomas laments the change in the definition of a black person from three-fifths of a human being. Some will protest after same-sex marriage is legalized, but they will soon realize that their lives have changed not at all, while the lives of their gay friends and loved ones--and everybody has 'em--have changed for the better. Just wait and see.