Attitude-Altering Slippery Slopes

[This month, I’m serializing my 2003 Harvard Law Review article, The Mechanisms of the Slippery Slope.]

“[T]he assault weapons ban is a symbolic—purely symbolic—move in [the] direction [of disarming the citizenry],” wrote columnist Charles Krauthammer, a proponent of a total gun ban. “Its only real justification is not to reduce crime but to desensitize the public to the regulation of weapons in preparation for their ultimate confiscation …. De-escalation begins with a change in mentality …. The real steps, like the banning of handguns, will never occur unless this one is taken first ….”

This is a claim about slippery slopes, though made by someone who would welcome the slippage. Decision A (an assault weapon ban) will eventually lead to B (total confiscation of weapons) because A and similar decisions will slowly change the public’s mind about gun ownership—”desensitize” people in preparation for a future step. (Note how this mechanism differs from the multi-peaked preferences slippery slope, which does not rely on people’s underlying attitudes’ being shifted.)

But how does this metaphorical “desensitization” actually work? Why don’t people simply accept decisions A, B, C, and so on until they reach the level they’ve wanted all along, and then say “Stop”? Why would voters let government decisions “change [their] mentality” this way?

Let me start with slippery slopes where a legislative or judicial decision increases the likelihood of a future legislative (not judicial) decision. Here, I think the slippery slope may be driven by what I call the Is-Ought Heuristic, and by what others have called “the normative power of the actual.”

In the wake of the September 11 attacks, Congress was considering the USA Patriot Act, which, among other things, may let the government track—without a warrant or probable cause—which e-mail addresses someone corresponded with, which Web hosts he visited, and which particular pages he visited on those hosts. Let’s call this “Internet tracking,” and let’s assume for now that this power is undesirable. This is our result B. Twenty-two years earlier, in Smith v. Maryland, the Supreme Court approved similar tracking of the telephone numbers that a person had dialed (the so-called “pen register”). This was decision A.

Curiously, most arguments on both sides of the Internet tracking debate assumed A was correct, even though a precedent holding that similar legislation was not unconstitutional might have at first seemed of little relevance in a debate about whether the new legislation was proper. The new proposals, one side argued, are just cyberspace analogs of pen registers and are therefore good. No, the other side said, some aspects of the proposals (for instance, the tracking of the particular Web pages that a person visited) are unlike pen registers—they are analogous not just to tracking whom the person was talking to, but to tracking what subjects they were discussing. Few people argued tha