Another possible interpretation of this graph is that in the US today, the feeling "I disapprove of X, so X should be illegal" is a much more common approach to

Another possible interpretation of this graph is that in the US today, the feeling "I disapprove of X, so X should be illegal" is a much more common approach to politics than it used to be. That's also my explanation for the "put people in jail for letting their kids play unsupervised" stuff that's been going on... Chances are, of course, that the graph reflects a combination of several factors.