Would you take his case?
Via Fark, check this story out.
I'd want to do some more research, but it doesn't look good for the guy. Wrongful discharge in Wisconsin is very narrowly construed (only where against a clear public policy as expressed by statute or legal duty, IIRC). Of course, if he is unionized, this probably wouldn't be "for cause" unless the CBA lists drinking the competitor's beer as a capital offense.