All in the spirit of "the best defense is a good offense," personally and politically, it's not out of the realm of the possible. Witness the proponents here.
Not really in the "non-destructive experiment" category, but solidly in Mr. Gingrich's "right wing social engineering" category.
May depend on who controls the legislatures, except where it's a local prerogative, in which case it might happen sooner.
Quis custodiet ipsos custodes?