Would Legal Pot Change Drinking Habits?

Jesse Singal mulls the question while reviewing Marijuana Legalization: What Everyone Needs to Know:

[F]or every question where the authors provide a clear answer, many points of ambiguity remain. One of them is the question of whether legalizing marijuana would increase or decrease alcohol abuse—would people drink more because they smoke more and enjoy combining the substances, or would their desire for some form of intoxication be sated by their increased marijuana use? Research is unclear on whether there’s a correlation, and, if so, in which direction it points. But alcohol is so much more dangerous a drug than marijuana, [co-author Mark] Kleiman said, that it would be perfectly rational to support or oppose the legalization of marijuana on this basis alone. "There’s no damage done by marijuana that can possibly make up for a 10 percent decrease in drinking," he explained—and, by the same token, no benefits that would justify legalizing it if doing so brought with it a 10 percent increase.