CBG, I am not playing games. Your post stated that " CURRENT use of either alcohol or drugs is NOT protected under the ADA." That isn't true because current alcohol use, in and of itself, does not lose an alcoholic ADA coverage (see the citation.) This is an important point and makes a big difference for the billion employed alcoholics in this country.
We are talking about who is covered by the ADA. Of course an employer can discipline for cause if the alcohol makes an alcoholic dysfunctional at work, no one is saying any different. Job performance is really not being discussed on this thread at all, except for you and Beth.
Whether or not you automatically lose cover may at times be situation specific, but the law is:
addict - using illegal drugs at work on or off the clock - lose ADA
alcoholic - Uses alcohol at work - no ADA
alcoholic - uses alcohol at home/not at work - you do NOT automatically lose ADA coverage.
Coverage only means you are covered by the law. Not that you have a guaranteed job.
If I have to write another word about this I'm going to have to go get that bottle out of my co-worker's drawer....