That's true, but correlation does not prove causation. I believe that the difference between the morality of the country in 1870 and of the country today is a much bigger factor as to why there are drug problems today.
The morality problem has created the need to make drugs illegal. If we can fix the morality problem, then I'm all in favor of going in the direction of freedom on this one.
Our Constitution was made only for a moral and religious people. It is wholly inadequate to the government of any other. - John Adams
Morality will never return to this country. Instead of outlawing drugs we should outlaw liberal thinking.
The US Constitution enumerates the powers granted to the national government by the States, and specifies the process by which they may be modified. Family Guy finding a "need" because of "morality problems" is not to be found.