A Justice Department spokesman says a bicycle messenger wearing a T-shirt that proclaimed ``Meese is a Pig'' was not admitted to its headquarters because he was ``inappropriately attired.'' ``Just as we would not permit somebody to come strolling in here with a bathing suit, for example, I think it's reasonable to have some kind of standard,'' spokesman Patrick S. Korten said Wednesday. He said the messenger, Christopher Stalvey, ``was inappropriately attired.'' Stalvey, who said the incident occurred June 10, visited the American Civil Liberties Union this week to tell legal director Arthur B. Spitzer about the encounter. ``We are prepared to bring suit if they say this is their policy,'' Spitzer said. ``It seems like a perfectly clear case of discrimination based on the content of the T-shirt.'' Korten, spokesman for Attorney General Edwin Meese III, said ``this is an interim policy until a firm determination can be made on how such matters ought to be handled.'' Korten ``obviously doesn't understand what the First Amendment is all about,'' said Spitzer. ``If they had a rule that said no T-shirts, that might be an acceptable rule. But apparently they have a rule that says no T-shirts that insult Ed Meese. Presumably, this guy would have been allowed in if he was wearing a T-shirt that said `Reagan-Bush '84'.''