Over at the Volokh Conspiracy, Eugene Volokh
blogs about how same-sex marriage, in Iowa and elsewhere in the world, has come about through a series of incremental steps through the steady acceptance of anti-discrimination legislation.
Of course, some people might like this slippery slope, because they like what's on the bottom. (See Deb Price, Marriage Is the Only Acceptable Option, S.J. Mercury News, May 23, 2002: "When Hawaii's steps toward legalizing gay marriage led to a backlash in Congress and many states in the mid-'90s, some gay-rights advocates felt the need to pooh-pooh the 'slippery slope' argument by foes that we'd ultimately try to push beyond any piecemeal rights thrown our way and would be satisfied with nothing less than full marriage. But not anymore. 'Our foes kept saying, 'This is a slippery slope to marriage,' and we kept nodding our heads, 'Yep,'' says [Anne] Stanback, unabashedly embracing marriage as the goal, just as do the movement's two top political groups, the Human Rights Campaign and the National Gay and Lesbian Task Force.") I myself support recognition of same-sex marriage as a policy matter. Still others may disapprove of the bottom of the slope, but might see some of the steps down it as morally imperative.
But it seems to me that decisions such as the ones in California, Connecticut, Iowa, Massachusetts, and Vermont ones illustrate that it's a mistake to just factually dismiss the claims that slippage is possible. When we're dealing with a legal system that's built on analogy and precedent (both binding precedent and persuasive precedent), the possibility of a slippery slope has to be taken seriously.