I would support what Dr. Kalant says. There is evidence from other countries that decriminalization actually does not increase use but actually helps to divert patients who have a problem to addiction treatment. In Portugal, for example, they decriminalized cannabis and it's had very good results.
On the other hand, legalization, as Dr. Kalant says, has been associated with dramatic increases in use and dramatic increases in harm. The two are completely different. I would support, and I think everyone I know would support, the decriminalization of small amounts of cannabis possession, but legalization and making it available in retail stores is a totally different matter.