Eugene Volokh requested in a post:
[E]xamples where (1) the opponents of some proposed law, constitutional amendment, or judicial decision argued "this action will be interpreted in this particular bad way" or "this action will set a precedent that will be used to reach this particular bad result," (2) the supporters assured the public that no, of course this won't happen, and (3) some time down the line -- preferably no more than 50 years, just to avoid especially hard questions of causation -- the foretold result did take place, despite the supporters' reassurances. (It doesn't matter whether you like the ultimate result or not; and it also doesn't matter whether you think the assurances were sincere or not.)
This is all in line with Volokh's research demonstrating that, in a legal system built on reasoning by analogy and citing precedents, the slippery slope is alive and well. (Although one criticism I might offer is -- if one looks at "the bigger picture" and sees the United States as one of many "Western" nations, what appears to be a slippery slope via judicial mechanism may be an illusion; as I've noted before, most Western European nations have been going through these exact social, cultural, and economic changes with, in many instances, the court system playing little if any role in bringing them about. So there is slippery slope in the West; I think, however, blaming the courts and the common law system for it may be shortsighted.)
There are many interesting comments on Volokh's post. However, they seem disproportionately to focus on sexual orientation issues. Therefore, I left the following comment.
I think one could argue that Loving v. Virginia sent us down the slippery slope that is leading to gay marriage (To make it clear: I support both the right of interracial marriage AND same-sex marriage).
The rhetoric condemning both interracial and same-sex marriages on grounds of "naturalness," "tradition," and "religion" are uncanny in their similarities.
And certainly, gay rights advocates use Loving as justification for same-sex marriage. Therefore if a court or public policy argument successfully uses Loving as part of the justification for same-sex marriage, we will have "slipped" from interracial marriage to same-sex marriage.
I stressed the interracial marriage point for a reason. Most traditionalist conservatives have come to accept and embrace both the Brown and Loving decisions (at least publicly). Yet, they also argue against same-sex marriage and much of the line of privacy cases, often on slippery slope grounds alone. For instance, Rick Santorum: "the court cannot say there is a right to homosexual conduct..." not because homosexual conduct is bad per se (although he does believe it bad per se) but because we won't be able to then say "no" to these other "bad" things completely unrelated to homosexuality. Or the classic, if we recognize a "right" to same-sex marriage, then we must also recognize a "right" to polygamy.
I'll be fair to the social cons; as Volokh demonstrates, we are on a slope and certainly recognizing a "right" to same-sex marriage (or to even same-sex conduct) supports expanding general liberty and equality rights to other unrelated areas. BUT(!) it's also equally true that the previous expansion of liberty and equality rights -- expansions with which we all now agree were proper like Brown, Loving, and Griswold (that last decision, probably more controversial among the social cons than Loving and Brown) -- led us to "slip" into decisions like Lawrence and Goodridge.
So for instance, it's certainly possible that a "right" to same-sex marriage could "slip" into a "right" to polygamy. But is it fair to then say "no" to same-sex marriage on the basis that it may help to justify an otherwise completely unrelated practice? If the answer is yes, then it seems to me that we could have also said NO to the Lovings on the ground that such a decision could "slip" into same-sex marriage.
It's certainly true that, when one makes an analogy between interracial and same-sex marriage we could draw meaningful social and constitutional distinctions. But it's also equally true that we can draw just as meaningful distinctions between same-sex marriage and polygamy.
This is what we do when we reason by analogy: to make an analogy is to compare apples to oranges. Comparing apples to apples is to compare duplicates. Whenever a court is confronted with extending the reasoning of case "a" to case "b" (or should I say case "a" to "o"), they always have at least two choices: Accept that the similarities between the two are more meaningful than the distinctions and expand the logic or the "right" to the new circumstance; or accept that the distinctions between the two are more meaningful and refuse to expand the "right."
For instance, Volokh's quote from Griswold:
[T]he Court's holding today ... in no way interferes with a State's proper regulation of sexual promiscuity or misconduct. As my Brother Harlan so well stated in [an earlier case in which he argued for a right of married couples to use contraceptives], "Adultery, homosexuality and the like are sexual intimacies which the State forbids ... but the intimacy of husband and wife is necessarily an essential and accepted feature of the in-stitution of marriage, an institution which the State not only must allow, but which always and in every age it has fostered and protected. It is one thing when the State exerts its power either to forbid extra-marital sexuality ... or to say who may marry, but it is quite another when, having acknowledged a marriage and the intimacies inherent in it, it undertakes to regulate by means of the criminal law the details of that intimacy."
Or from Griswold's oral arguments (hat tip):
THE COURT: Would your argument concerning these things you've been talking about relating to privacy, invalidate all laws that punish people for bringing about abortions?
MR. EMERSON: No, I think it would not cover the abortion laws Or the sterilization laws, Your Honor. Those--that conduct does not occur in the privacy of the home.
THE COURT: There is some privacy, as a rule, and the individual doesn't generally want it made known.
MR. EMERSON: Well, that aspect of it is true, Your Honor. But those are offenses which do not involve the type of enforcement apparatus as to what goes on in the home that this--
THE COURT: Part of it goes on in the home, undoubtedly.
MR. EMERSON: Part of it does, Your Honor. But the conduct that is being prohibited in the abortion cases [t]akes place outside of the home, normally. There is no violation of the sanctity of the home.
But we know that Griswold did "slip" into these results. But it didn't have to. It's entirely possible that a "right" to same-sex marriage will slip into a "right" to polygamy. Or not. Just as it's entirely possible for a "right" to interracial marriage to "slip" into a right to same-sex marriage...or not. But the slippery slope precautionary principle, if consistently followed, would have left governments free to forbid contraception between married couples and interracial marriages.
Finally, in terms of how long we've been "slipping," arguably we've been "slipping" since 1776. Most of the "slipping" that has been occurring is the ever expansion of liberty and equality rights to new areas. Liberalism, as encapsulated by the Declaration of Independence, is the twin principles of liberty and equality. Note, I agree with Robert Bork and Allan Bloom that the Declaration of Independence and classical liberalism logically demand many of the modern socially liberal results. From Thomas West quoting Allan Bloom's The Closing of the American Mind:
This is a regime founded by philosophers and their students. . . . Our story is the majestic and triumphant march of the principles of freedom and equality, giving meaning to all that we have done or are doing. There are almost no accidents; everything that happens among us is a consequence of one or both of our principles. . . . [T]he problem of nature [is] always present but always repressed in the reconstruction of man demanded by freedom and equality. (97)
When we were first founded on our broad Enlightenment ideals of liberty and equality, there was a historical consensus that these "rights" only belonged to white, propertied, Protestant males. Some of the more visionary thinkers (our key founders: Washington, Adams, Jefferson, Madison, and Franklin) desired rights to have a broader application, to apply to blacks and all (even the unorthodox) religions. But even these Founders were, in many ways, greatly affected by the historical consensus. It's doubtful that any of them desired the full integration of blacks into regular (white) society or, God forbid, giving women the right to vote or letting them outside of the home.
This is why often, it is hard to properly determine what is foundational to America. Often the results depend entirely on whether we "freeze" the Founders in their historical context and examine the comprises they made with broad ideals of liberty and equality, or rather if we examine those broad ideals as ends unto themselves. By "freezing" our founders in historical context, social conservatives can demonstrate that our Founders didn't believing in "rights" for pornography, homosexuality or anything else to do with our modern looser sexual mores. But then again, those founders also practiced slavery, denied women the right to vote, kept them in the home, etc. etc. Liberty and equality as ideal ends in themselves got blacks out of slavery, gave women the right to vote and into the workplace, disestablished all churches and formally granted religious rights to Jews and other non-Christians; but this perspective also militates in favor of modern socially liberal results, because this is the liberal, enlightened tradition of expanding liberty and equality rights.
So ultimately, I think we don't have reason to "fear" the slope because "the slope" in question, really means more liberty, more equality, and a broader more consistent application of these rights. If anything, we have reason to fear refusing to expand liberty and equality rights, because more often than not that is refusing to do justice (see Loving, Brown, Griswold, etc.). Most of the "slippage" on the slope, I would argue (certainly with key reservations -- the topic of another post) has led to desirable results that a consensus of society eventually accepts.