Thank you ubernostrum. So, in my proposed scenario of us bringing back a case of wine, we need to comply with the New York law (which looks like anything over 1 litre requires the filing of a MT-39 Tax Form and the payment of excise tax in the amount of .079 per litre), Montana law which is totally unclear, and Federal which looks like it wouldn't be a problem. There is lots of misinformation out there on this subject and I have found very contradictory summaries of the laws. It appears TSA doesn't care how much wine you bring as long as it is not in the cabin (then 3oz rule applies) and then there are of course carrier specific rules which may further regulate things beyond the simple weight/piece concepts.

I am getting the feeling that I will not be bringing back the case of wine unless I have the desire to hire a couple of importation attorneys so sort out all the complications in the laws and fill out the paperwork required.

In the end I guess it is an extremely complicated answer to a fairly simple question.