Drug and alcohol abuse is a significant problem in contemporary American society. Taxpayer dollars are spent at every level of government to address the issue. If you could direct the discussion, what is the one area of this problem you believe should be the prime focus? For example, should we make prevention our top priority? Decriminalization? Access to treatment and rehabilitation programs?
I would focus on treatment and rehab. Prevention, as the "War on Drugs" has proven, only goes so far. So long as there are people who want to get 'stoned' there will be supplier. We can make it very difficult, and we can try to discourage it, but it is impossible to erase every supplier and demander.
Decriminalization is a very sticky issue. "The (marijuana) Genie is out of the bottle" in Washington and Colorado, and there may be no way to get it back in, but using drugs and alcohol doesn't just harm the user. Dozens of cold sober drivers are killed by intoxicated drivers every day. Children are orphaned by overdosing parents, babies are explosed to toxic chemicals in utero by using mothers, families are abused by "high" family members. Trying to find the line where it ceases to be danger to just the user, and a danger to the public is where that could go.
Treatment and rehab is the most fruitful of areas to pursue. Criminal or not, drugs and alcohol do have adverse effects on the abusers, and many drugs are addictive which makes quitting "cold turkey" torturous. But we are at least trying to help those who have gone down this road, and we might find new ways to help them by discussing options.