After a quick read through of your post I will at least give you a few of the initial thoughts I had as to what walls and rebuttals you could potentially run into regarding your counters.
Social Conservative: Alcohol is immoral too and/or why should we add another negative behavior to the list then?
Progressive: interestingly enough on the basis of the assumed argument/counter a similar rebuttal to the conservative.. why add another?? Hit them with freeing up of monies from legal proceedings and incarcerations and let them fill in the blanks as to what that money can be used for.. perhaps suggest that a fraction of the criminal justice savings can go a long way towards education prevention and rehabilitio, and thus potentially offset the harm you conceded in the long term.
Economic Conservative: with your counter argument their first thought may be.. how do we deal with loss of productivity due to alcoholics?
Liberal: gloss over the thoughts on public smoking, many people (not just liberals) would rather not see it an option in public at all, mere mention of this instantly brings up thoughts and images of public intoxication driving while intoxicated and since i made mention of that.. quick tangent ty for the saliva test link, that is news to me, I need to look into that more.
Libertarian,, I would stay away from the studies show people are safer drivers argument as much as you can, it is always met with incredulity, and people will automatically start to doubt your credibility before you even have a chance to elaborate.. plus despite the studies they are still intoxicated, and they are likely only appearing to be safer because they are driving like paranoid old ladies. best avoid that argument altogether
edit:well i was gonna edit this a bit when i saw it was sloppy and kinda hard to read, but its 5am, which also explains why it is sloppy in the first place. no edit other than this disclaimer... too tired.