Have you heard the one about the new movie called "Jews"? It's the story of a small resort town terrorized by a loan shark.

Now I think that's pretty funny. And, I'm sorry, I just can't find enough high-mindedness within me to wish that this sort of joke didn't exist.

President Reagan told a good one in Venice the other day. As per usual, he thought the microphone was off. It seems there was this gondolier singing "O Sole Mio" and the Lord wondered what would happen if he lost 25 percent of his brain power. Result: he sang "O sole, O sole." So the Lord took away half his brains and he sang, "O so, O so." Finally, the Lord took away all his brains and he sang, "When Irish Eyes Are Smiling." Refreshingly, there's been no fuss. Reagan has uttered so many boners over the past seven years that people have become numb.

Of course it's undeniably true that ethnic jokes affront the brotherhood and sisterhood of all humankind, as well as the individuality of each person. But a world of universal and constant respect for these ideals might be hard to live in -- and, in any event, is not on the horizon.

There are those, no doubt, who can refrain from telling ethnic jokes. And there may even be some -- a much smaller group, and one you probably wouldn't care to share a long cruise or jail term with -- who can refrain from laughing at any of them. As for the rest of us, what we need are some guidelines aimed at providing maximum gaiety with minimum offense. Here are a few suggestions.

Rule 1. As Reagan noted, it's better to tell jokes on your own ethnic group. He's Irish, I'm Jewish. Of course Reagan doesn't really believe that the Irish are inordinately stupid and I don't really believe that Jews are inordinately avaricious. But an ethnic joke told on oneself can become a way of laughing at the stereotype, thereby undermining it, rather than promoting it.

Rule 2. If the joke is about some other ethnic group, a good test is whether you would tell it to a friend from that group. If you'd be embarrassed to tell the joke in front of your friend, maybe you shouldn't tell it elsewhere. If you don't even have a friend from this particular group, that's an even better signal to stay away.

Rule 3. Jokes about some groups are less offensive than jokes about others. This is a valid double standard. Black Americans are still everyday victims of oppression and discrimination based on ethnic stereotypes; Italian, Irish, and Jewish Americans far, far less so; WASPs not at all.

Unfortunately, most WASP jokes just aren't very funny. They have a sense of strain, almost a sense of duty about them, not a sense of natural vicious inspiration. Many are actually jokes at the expense of other groups -- variations on "What do you get when you mix a WASP and a Puerto Rican," and so on. This illustrates the unavoidable truth that a good ethnic joke must contain an element of gloating superiority. It can be vestigial, but it must be there. A well-meaning naif once suggested that we should invent an all-purpose imaginary group to be the butt of ethnic humor. Unfortunately, it wouldn't work.

Rule 4. Jokes about certain alleged traits are more offensive than jokes about others. This has nothing to do with the validity of the stereotype involved. For example, it is not true that certain ethnic groups inherently smell bad and/or attract insects, and jokes based on this premise are pointless and disgusting. On the other hand, a whole genre of jokes has surfaced in recent years based on the equally false premise that all Jewish women are frigid (the reverse of the traditional stereotype). In that case, the absurdity of the premise turns it into a harmless convention.

Jokes about drunkenness, laziness, greed are more tolerable than jokes about physical characteristics or personal habits. The tough call is stupidity, since it implies genuine and immutable inferiority, and yet is the basis of probably half of all ethnic jokes, including some good ones. One comfort here is that the literature lacks any clear consensus about which groups are ostensibly dumber than others. Reagan's joke turned on the Irish being dumber than Italians. "Totally Gross Jokes, Volume II" has a similar joke about progressive loss of brainpower whose punch line is "Oh, mama mia!"

Rule 5. If you tell an ethnic joke, make sure it's funny. Most ethnic humor in the recent rash of paperbacks and on those gross-out radio talk shows is witless. Wittiness is important not only for its own sake -- to compensate for any offense -- but as a test of motive. An unfunny ethnic joke is merely an expression of contempt. A funny one need not be.

Rule 6. If you hear one you think is good, feel free to laugh. Examine your conscience later. It's healthier that way.