On the Other Hand...

In response to something I just said a few hours ago. On the other hand, using the political process to purposefully create social experiments has some significant downsides. Namely, that it's almost always a non-random process, and secondly, there's a ratcheting effect with laws passed, particularly bad ones.

The non-random part of it makes it very difficult to interpret outcomes as genuinely causal. Oftentimes, laws are passed to do things that have little to nothing to do with the things being addressed - which is partly why social scientists get obsessed looking for random accidental laws passed that don't really have anything to do with the underlying phenomenon addressed. For instance, like Martha Bailey's "More Power to the Pill: The Impact of Contraceptive Freedom on Women's Life Cycle Labor Supply". In it, she examines the impact of laws that made it illegal for 18-20 year old females to have access to the pill. The ingenuity is that she does not use laws which were meant to do this - she uses law changes borne out of the "age of eligibility" legislative movement. The Vietnam war brought about the contradiction between the age eligibility of the draft (18) and the age of eligibility to vote (21). Several states lowered the latter age to 18, and by the mid-1970s, I think all states had done so. This not only enabled 18 year olds to vote, though - it also enabled 18-20 year old females to get a prescription for the birth control pill, and the legislative change was done entirely for reasons unrelated to their own fertility choices. While I agree generally with Posner's point that social experimentation is important, how much closer does it actually get us to saying that the law is the best way to do it? How many states will randomly select jurisdictions to tax transfat or ban it or whatever? Rent-seeking and other factors will affect the selection of those jurisdiction. This works against the support for transfat bans, I think.

The other problem in my mild support is that bad laws have a way of sticking around way longer than they should. They call this a "ratcheting effect." So say we use these laws to satisfy our curiousity, and then learn the laws have no health benefits, and only increase social costs. Inefficient, so rid ourselves of them, right? Good luck with that.