The Politics of Marijuana

| by The Volokh Conspiracy

By Ilya Somin

Pete Guither has a helpful roundup of reactions to the defeat of Proposition 19, which would have legalized marijuana under California state

law. Opinion seems to be divided between those like myself and Kevin Drum who believe that support for legalization is rising and those who claim that the cause is probably hopeless because of opposition by parents and the elderly (e.g. Tyler Cowen and Megan McArdle).

I continue to be optimistic about public opinion trends. Gallup data shows that support for marijuana legalization has slowly but consistently risen from 12% in 1970 to 46% today. This is exactly the percentage of the vote that Prop 19 got, despite the fact that the elderly (who tend to oppose legalization by large margins) were vastly overrepresented in the 2010 California electorate. This longterm trend strongly supports my theory that disproportionate opposition to Prop 19 among the elderly is a generation effect (caused by ideological differences between younger and older generations) rather than a cohort effect (caused by people becoming more anti-legalization as they get older).

Megan McArdle and Tyler Cowen emphasize the role of parents in opposing marijuana legalization. It is indeed true that parents are more likely to be against legalization than others. But as Bryan Caplan points out, the impact of parenthood is minor compared to that of other factors such as ideology, gender, and religion. Moreover, parents, like other groups, have become less opposed to legalization over time. Today’s parents are more likely to oppose legalization than today’s childless adults. But they are still more supportive than the parents of 10, 20, or 30 years ago.

On balance, therefore, I think the trend towards greater support for marijuana legalization will continue, which cuts against Tyler’s theory that Prop 19 was the “high-water mark” for the legalization cause.

That doesn’t automatically mean that legalization will actually happen. Public opinion is not the only determinant of policy. Interest group influence matters too, and there are some powerful ones opposed to legalization (including the prison industry, various law enforcement agencies, and others). It is also possible that unexpected events will reverse the current trend. Although I don’t consider it to be likely, it’s possible that the next generation will be more socially conservative than today’s young people. It’s also possible that the trend towards support for legalization will be undercut by some dramatic negative event, such as the death of a prominent celebrity from a marijuana overdose. It would be irrational for voters to change their minds about legalization because of such an incident. But ignorance and irrationality are major factors in public opinion.

Despite these caveats, the data suggest that legalization advocates have more reason for optimism than their opponents. The long-term trends seem to be in their favor.