I wanted to see what others said before posting my comments.
First thought: Just another bill intended to get someones name in the paper, as this obviously will not go anywhere, without some serious Congressional lobbying. He admits that himself. Thousands of similar bills that don't go anywhere are introduced each year.
Second thought: Great idea, in theory. However, some expensive training would have to be done across the state for liquor establishments, to be able to recognize proper military IDs and make sure it isn't a dependent. Also, what rules are going to be in place for Reservists/Guardsmen that are not currently on active duty for drill weekends or deployment? If this went through and they were allowed to drink while not on active duty, me thinks the Wisconsin ANG/ARNG and local reserve units will be meeting recruiting goals 100%+.
Third thought: For any active-duty installations in Wisconsin, what happens to the servicemembers that choose for one reason or another to keep the citizenship of another state? "Sorry Mike, can't go to the bars with ya, I'll rather be a TX resident and not pay state tax...". This type of situation also makes buying for a minor a very confusing area.
Fourth thought: Miller Brewing Co. calls Milwaukee home. Me smells a rat???
Conclusion: The state senator, if serious about wanting troops to drink and not just wants his name in the paper, would be better off having the state legislature create a law/memorandum highly encouraging commanders of military installations to lower the drinking age of such installation for troops. That way, servicemembers could drink in the state (just as long as they are on a military base), with none of this "locals only" stuff, and most importantly, without getting Congress involved.