After seeing what has happened in Colorado (and many other states) and the entire country of Canada, I'm curious to learn why you oppose legalization?
I don't use it, and personally don't really care, but I see it like same-sex marriage - let people do what makes them happy and lets move onto actual important issues.
For starters, a 20% increase in violent crime and significant increases in hospitalizations[1] directly related to marijuana use are two concrete examples. There are many more less-direct negative effects (e.g., insurance rates increasing for everyone due to marijuana-related accidents/injury) that probably aren't immediately reflected in public data, but are still detrimental to society.
[1] https://cdpsdocs.state.co.us/ors/docs/reports/2018-SB13-283_...
[0] https://crime-data-explorer.fr.cloud.gov/explorer/state/nebr...
While this is an ostensibly neutral collection of data, it reads to me very favorably about effects of legalization. Surprisingly even vehicle fatalities decreased significantly over the measured time period.
"violent crime increased 20% from 2012 to 2017"
If you graph the data presented in table 46, the increasing trend – specifically in violent crime since 2012 – becomes very clear.
I'm also not seeing any significant increase in insurance rates after my state ended prohibition, and the traffic fatalities and collisions haven't been significantly impacted.
What explanation do you propose for why cannabis legalization would lead to an increase in violent crime?
Anecdotally, the people I know who use marijuana drive high regularly and don’t think that doing so is dangerous, despite overwhelming evidence to the contrary.