"Targeting" is beginning to emerge as the key political concept in the Democratic Party's search for a response to Ronald Reagan and his program.

The meeting last weekend of the Democrats' new National Strategy Council--a collection of several dozen elected federal, state and local officials--produced nothing that could be dignified with the label of a policy alternative to the economic, defense or social policies of the Reagan administration.

But listening through nine or 10 hours of sometimes spirited discussion among these mostly very bright, under-50 Democrats, you could get a sense of where the party may be going.

Their fundamental criticism of Reaganism can be summarized in that derogatory exclamation of teen-agers: "It is gross."

Gross in the sense of excessive. Gross in the sense of crude. Gross in the sense of awkward. Gross in the sense of poorly defined.

One reason that the Democrats have been slow in formulating their indictment of Reagan's policies is that he is personally none of those things. He is trim, tasteful, graceful and eminently clear about his purposes.

But as you listened to the Democrats talk-- and, more importantly, as they listened to each other, in the valuable get-acquainted format the council provides--you could hear them trying out variations on what might become the party theme for 1982 and 1984. That theme is "targeting."

In the economic area, they were saying that Reagan's tax cuts, budget cuts and regulatory reforms were, in every sense, gross. The tax cuts were too big, threatening excessive deficits. The budget cuts were too big, threatening lifeline support systems for people and needed investment in the social capital of transportation, technology and education.

Deregulation was too rapid, heedless of consequences for competition and the environment. In their eagerness to dismantle the old rules, they said, Republicans were planting oil wells on scenic coastlines. Instead of encouraging small firms in growth industries, they were allowing mergers of giant companies, a spectacle which economist Walter Heller said reminded him of dinosaurs mating--a gross image if there ever was one.

In his handling of federalism, they maintained, Reagan's approach was equally crude. Rather than a careful sorting of the programs best handled by different levels of government, he was--the Democrats maintained--engaged in a headlong process of ditching federal responsibilities and loading them onto the states and cities, whether or not they were fiscally or administratively ready for them.

In the area of national defense, they said, Reagan was for doing everything now--and hang the cost. The recent decision to proceed with MX missiles and B1 bombers and Stealth aircraft all at once was expensive, excessive and --gross.

Similarly, in the area of diplomacy. Rather than dealing with all the shadings of character in the governments of the world with a subtly tuned foreign policy, the Democrats maintained, Reagan is classifying everyone as friend or foe, showering weapons on the friends and invective on the foes. A gross oversimplification.

Is this a start on a strategy--or just a catch- phrase? A tentative answer may be offered by next month's New Jersey gubernatorial election, where Democrat Jim Florio is offering "targeted" tax cuts and limited program trims, in contrast to Republican Tom Kean's proposals for Reaganesque slashes in corporate taxes and state spending. But whatever the result of that close contest, it will be but a partial test of the larger proposition.

What Democrats have yet to prove nationally is that their "targeting" approach is more than watered-down Reaganism. Neither Florio in New Jersey nor the Democrats nationally have provided the specifics that are there in the Republican programs they criticize.

When Republicans took a similar 1ine against then-dominant Democrats, they were accused of having a "me-too" philosophy. Today, most Democrats echo Reagan's arguments. They say taxes should be cut, federal programs pruned, regulations eased, investment increased, state and local governments trusted, defenses improved and foreign relations strengthened--but carefully. In a targeted way.

Their challenge is to spell out what they mean. And they say they are ready for it, that they have found economists as unknown as Art Laffer was five years ago, defense specialists as anonymous as John Lehman was then, who are eager for the challenge. These young Democrats --the Gary Harts and Jerry Browns, the Tim Wirths and Dick Gebhardts, the Madeleine Kunens and Peter Shapiros--are certainly up for the game themselves.

If you believe that competition is as good for politics as it is for business, then the "targeting" debate will be healthy for this country.