IT WAS COGNAC or maybe Amoretto, but whatever it was, it kept coming to the two of them. They were sitting across from each other at a restaurant table, debating, playing with concepts, taking a sip or two of whatever it was they were drinking, and then returning to the fray. They were both lawyers, both brilliant and fast on their feet, both putting on quite a show arguing, would you believe, about Marvin Mandel.

This was before the trial. This was before the guilty verdict and the four-year jail sentence and all that. This was a night in a Washington restaurant and the debate had nothing to do with whether Mandel was guilty or innocent, but instead whether the government had done something terribly wrong in indicting him.

The lawyers had met by accident and they asked afterwards that I not name them. One of them, though, was progverment, an admirer of the indictment, one of those who thought this was creative use of the law. The other took the opposite view. He was appalled and he said so. A friend and I did the listening. We said nothing and then when the night was over and I had promised not to mention any names, everyone went off, shaking hands and agreeing it had been fun.

What brings this to mind now is the appeal filed last week in the Mandel case. Some of the arguments are the same heard that night in the restaurant, argument that seemed telling at the time, but which dissipated when the trial itself began. Then you saw Marvin Mandel and his codefendants on the stand and you were troubled more by what they said - or did not say - than anything having to do with th eindictment. None of is was pretty.

It is not pretty to have a governor come across as everyone's favorite charity - sults from this friend and vacation trips from that friend and divorce money from someone else ad jewelry for a wife on her way out. There was all that and then there was all that business with Mariboro Race Track, how it was bought secretly by Mandel's friends and how it benefited, from what the state and the governor did and, finally - an. Eastern Shore real estate proposition and an office complex in the Baltimore area.

All of this locked bad - bad enough for a jury to convict. But it did not convict on bribery, but on something else - mail fraud and racketeering. It all added up, the government said, to a scheme to defraud the people of Maryland, but what the lawyers for Mandel are saying in their appeal is that it all adds up to a crime that did not exist before - crime based an acts that heretofore were legal in the state of Maryland.

Anyway, the thing gets complicated and it gets into Latin terms but there are some things that stand out in plain English, which was the language used by the lawyers that night in the restaurant. What one of them said in defending the Mandel case was that the government had to be "creative" in its indictment - that the state would never prosecute its own governor for corruption. Laws were being broken and something had to be done, the lawyer said.

He was a point. Something is wrong in the style o f Maryland and something had to be done about it. The last two governors of the state have either been convicted of corruption or have pleaded guilty to it, and the same is true if the last two county executives of Baltimore County. You can go on like this, listing the savings and loan scandals and the conviction of Anne Arundel County executive Joe Alton and the fact that emerges starkly is that these are al federal prosecutios. State prosecutors either can't or won't do the job and certainly, at the Mandel trial proves, there was a job to be done.

But none of what Mandel did was really mail fraud and certainly none of it was racketering. Some of it smacks of bribery and some of it political corruption and all of it smacks of ethical laxity, conflict of interest and all the rest, but not what the Congress had in mind in the rest, but not what the Congress had in mind when it passed its antiracketeeing statute. There is nothing about Mandel or the others that is in the least way reminiscent of screeching cars and running boards and Tommy guns. Racketeers they are not.

The point is not whether Mandel is honest or dishonest, but rather that the criminal low should be exact. It should say what it means and mean what it says. There are, after all, worst dangers than a governor with a yen for expensive suits and it was mentioned that night by theat lawyer in the restaurant. He said he feared laws that say whatever a prosecutor says they say.

The waiter's long aog, but I'll drink to that.