Eugene Volokh has an intriguing post about unreliable assurances, with examples that speak for themselves.
I'm looking for examples 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.
The examples he cites, and many others, explain why libertarians are so wary of even tiny baby steps towards rights restrictions -- the so-called "slipperly slope" argument. Professor Volokh's post is particularly interesting because he's often a harsh critic of slippery slope arguments, rightly pointing out that slopes often can be avoided. However, as these examples demonstrate, they often are not.
This fear of a slippery slope is why I oppose gun registration laws -- registration is a clear first step towards a ban and confiscation. Registration is how, gasp, the Nazis and Communists began disarming their subject people. Likewise, I'm sympathetic to those who oppose greater police power designed to combat terrorism even though, yes, the power can and will be misused at some time. I've tried to account for that inevitable occasional misuse, however, in my decision to support some controversial laws, such as the Patriot Act.
"The examples he cites, and many others, explain why libertarians are so wary of even tiny baby steps towards rights restrictions -- the so-called "slipperly slope" argument."
Where did 'rights restrictions' come from? That's just the projection of libertarian fears. Two of Volokh's three examples run the other direction: They're the destruction of social norms. They're limits on government, not limits on individuals.
I don't think that slippery slopes run any particular direction to the left or right, or toward or away from governmental power. A slippery slope argument is really just about the existence and power of fanatics.
A slippery slope argument on guns, for example, starts with the assertion of some fanatics. A significant group of Americans, for example, would like to completely ban any weapons more lethal than kitchen knives and slingshots. Lots of people would like to repeal laws against polygamy and pedophilia. And there are plenty of people who would like to force some religious vision of morality on us.
The argument, whatever its starting set of fanatics, then goes on to assert that these people are somewhere close to having enough power to bring their horrible views into law, and that the proposal under discussion will help them in achieving that goal.
In a nation this size, no one can deny that there must be some weirdos out there who would like to create just about any horrible law you can imagine. So the existence of these fanatics is nearly impossible to deny. The tough question, and the proper focus of any slippery slope argument, is: In the future, will the fanatics actually possess enough power for us to worry about?
The trouble with these arguments is that they usually convince no one, because the future power of the fanatics is inherently unprovable. You can't just take a poll on it; it's a question of political effectiveness. The fantics could be any combination of numerous, motivated, organized, occupying positions of power, geographically concentrated, or simply willing to work longer and harder than the rest of us on their narrow issue. And beyond the qualities of the individual fanatics is the question of how the future zeitgeist will aid or hinder their cause.
It’s nearly impossible even in theory to measure something as subtle as future political influence, so no one can ever really prove or disprove a slippery slope argument. It just boils down to: “What you want would allow the dangerous fanatics to do horrible things,” compared to: “No, it won’t.”
-- Where did 'rights restrictions' come from? That's just the projection of libertarian fears. Two of Volokh's three examples run the other direction: --
I would agree. What I took to be the focus of Volokh's post (or at least what interested me the most) is that we have been slipping in rights expansion (mainly in social and cultural areas) and I argue in my post that these results -- the expansion of liberty and equality rights -- (what Ben calls "the destruction of social norms") have been by in large, good results that a consensus of society eventually accepts.