With 16 states having decriminalized or legalized cannabis for non-medical use and eight more heading toward some kind of legalization, federal prohibition's days seem numbered. You might wonder what America will look like when marijuana is in the corner store and at the farmers market. In three years spent researching that question, I found some ideas about the plant that just don't hold up.

1. If pot is legal, more people will use it.

As drug policy undergoes big changes, I've been watching rates of youth cannabis use with interest. Whether you like the plant or not, as with alcohol, only adults should be allowed to partake of intoxicating substances. But youth cannabis use is near its highest level ever in the United States.