Tests which were proposed in the comments include whether a person favours legalization of marijuana, [...]

This is actually a good test, but not in the way it was intended. Drug laws are not about drugs, and I expect someone who claims a high level of rationality about political issues to understand this point. So when someone discusses the issue of marijuana prohibition by doing some sort of cost/benefit analysis that takes the purported motives of these laws at face value, I find this to be a miserable failure, no matter what his ultimate conclusions.