ON TUESDAY, Angel Nunez will enter the courtroom. The government lawyer, having flown down from Boston, will take his place and so will Nunez's lawyer, a Washington attorney named Rande Joiner. The judge will enter. Everyone will probably rise and the charges will be read: Did you, Angel Nunez, take, possess, purchase, barter or offer to sell or transport at any time or in any manner a bald or golden eagle, alive or dead, or any part, nest or egg thereof of the foregoing eagle? How plead you?

Stop. We zoom in on Angel Nunez.He is a short man, dark and intensely bearded, 35 years old and a native of Spain. He is a taxidermist by training and now owns an antique store in Washington called, logically enough, Angel Nunez Antiques. We look past him to the eagle. It is a golden eagle, fierce and ugly looking, brown with white flecks, its wings held close to the body. It stands on a pedestal, a dead bird about to fly nowhere. It has been dead since around 1920 when somewhere in Spain someone took it down with a rifle. I'd like to think it was Hemingway.

Now it is 1960. A young Angel Nunez, dark and intensely bearded and practicing the yucky craft of taxidermy, is strolling through the Madrid flea market. He spots the eagle. He buys the eagle and in 1973, when he comes to live permanently in the United States, he imports, along with such things as elephant paws and other delectibles, the forementioned eagle. He clears customs. He sets himself up in business and in 1978 he opens his antique store.

Now we are at the store. It is located up one flight of stairs, a bit south of Dupont Circle. Scattered around are the playthings of the rich - old furniture and old rugs and what is known in the better neighborhoods as objets d'art. It is April 21, 1978, and into the store comes agent Marcia Cronan of the Fish and Wildlife Service, Department of the Interior. She seizes the eagle in the name of the United States of America and hands the stunned and disbelieving Angel Nunez something called a seized property receipt: Article Seized: eagle, a possible golden or Spanish Imperial. She takes the eagle and leaves.

For over a year now, the government of the United States has been battling Angel Nunez over this particular stuffed and deceased eagle. The eagle has been taken to the Smithsonian Institute where experts have declared it (a) a golden eagle (b) a bald eagle (c) no such thing. No one contests that it is a very old eagle and very dead eagle. No one challenges Nunez's assertion that the eagle met its doom in Spain around 1920 - an assertion he says can be verified by any taxidermist.

"You can tell by the skin," he avers.

No matter. This is not the issue. The issue, as far as the government is concerned, is whether Nunez was attempting to sell the eagle. If he was, he was breaking the law - a law he did not know existed, but breaking it nonetheless. He insists the eagle was not for sale. He says . . . we'll let him speak for himself. Ladies and Gentlemen, Angel Nunez:

"I open the store in February 1978. Only one year I been here. I didn't have nothing in the store. I didn't have nothing. I started with $3,000 which was loaned to me by a friend of mine. So I bring everything from my house. Everything from my bedroom. I bring the eagle. I never want to sell the eagle. I had to put something in the shop because it was empty. I needed to put something. I put the eagle in the window. It's not for sale. People ask me what I want. I say, 'It's worth $2,500. But it's not that I wanted to sell it. I had no intention to sell it. I don't want to sell it. That's why I ask such a high price."

Maybe and maybe not. It's hard to say for sure that Nunez would not have taken $2,500 for the eagle. You can understand, also, why the government would have its suspicions. You can understand, also, why the government would want to forbid trading in eagles. They are a rare species and one way you save them is by drying up the market. If you can't sell them there's no reason to kill them. It is a wonderful law, passed a bit late to do any good for the bird that Nunez used to have in its window. No matter, the government wants to prosecute.

Now the fact of the matter is that when you run across something like the Nunez story you expect that when you call the "other side" - in this case, the government - what appears to be silly will suddenly make sense. It did not happen here. A government lawyer named Abner Cooper said he's coming down from Boston on Tuesday to try Nunez before an administrative judge of the Department of Interior. Cooper, I have to tell you, really does not care how old the eagle is or what it's country of origin might be - just what the law says. The law, he says, says that Nunez did wrong and he is asking a$500 fine and confiscation of the eagle. With the exception of the fine, this is something Nunez already proposed. He has offered to donate the eagle to the Smihtsonian. The government has turned him down. The goverment will make Republicans of us all.

So now let's pretend it is Tuesday again and Angel Nunez is standing about to say his "not guilty." Around him are lawyers and stenographers and a judge. There has to be another hearing and then maybe a trial in circuit court. Lawyers will fly the country and files will opened and closed. In the end, either the government or Nunez will get the eagle, but one thing is for sure.

The taxpayers will get the bird. CAPTION: Picture, Stuffed golden eagle is at issue.