Maia Szalavitz asks whether Prop 19's passage would increase cannabis use:
One thing the [International Centre for Science in Drug Policy (ICSDP)] report makes clear is that current U.S. drug policy has no effect on marijuana prices or use. While spending on federal drug law enforcement has increased 1,200% and marijuana arrests have risen 150% since 1981, the rate of marijuana use nationwide has bounced around, with no relationship to these efforts. ...
One study did find that rates of marijuana use among Dutch youth increased when "coffee shops" cafes where selling and smoking of marijuana are permitted were proliferating and being widely marketed. But, overall, even those elevated rates of use were no higher than U.S. rates under marijuana prohibition. "It wasn't the decriminalization, it was commercialization that could have caused this," says Kilmer.