Unfortunately, THE WEEKÂ magazine didn’t publish this excellent blurb on their site, but it ran in the 6/28/2013 print edition. I thought it was such an excellent critique of a too-common rhetorical technique that I wanted to post it here:
Logicians call the slippery slope a a classic logical fallacy. There’s no reason to reject doing one thing, they say, just because it might open the door for some undesirable extreme; permitting “A” does not suspend our ability to say “but not B” or “certainly not Z” down the line. Indeed, given the endless parade of imagined horribles one could conjure up for any policy decision, the slippery slope can easily become an argument for doing nothing at all. yet act we do; as George Will once noted, “All politics takes place on a slippery slope.”
That’s never been more true, it seems than now. Allowing gay marriage puts us on the  slippery slope to polygamy and bestiality, opponents say; gun registration would start us sliding into the unconstitutional morass of universal arms confiscation. An NSA whistle-blower, William Binney, said last week that the agency’s surveillance activities pus on a “a slippery slope toward a totalitarian state.” And this week we’re hearing a similar argument that President Obama’s decision to arm Syrian rebels, however meagerly, has all but doomed us to an Iraq-style debacle. These critics may be right to urge caution, but in their panicked vehemence, they’ve abandone nuance and succumbed to the summoning up worst-case scenarios.
UCLA law professor Eugene Volokh points out that metaphors like the slippery slope “often start by enriching our vision and end by clouding it.” Decriminalizing marijuana doesn’t have to turn the U.S. into a stoner nation, nor does sending M-16s to Syrian rebels inevitably mean boots on the grond in damascus. But that’s not to say we shouldn’t watch our footing.