A small wedding reception in a small, newly redecorated Capitol Hill house. The guests are a mix: Kennedy Center executives, artists and agents, lawyers, assorted Yuppies, a couple of Old Washington Hands.

The bar is in the kitchen: half-gallon jugs of Scotch, bourbon, gin, vodka, rum. The odd fifth of tequila, a fine old brandy. A rack of wine bottles behind the door, a huge jug of red on the counter and a refrigerator full of beer. It is a hot afternoon.

"What can I get you?" the host says to five newcomers.

The orders:

One white wine, one white wine spritzer, one ginger ale, two club sodas.

Nobody says, "Whatsa matter, you onna diet?"

Nobody says, "Hey, come on."

Nobody gapes, grins, shrugs or wheedles.

In fact, nobody bats an eye.

Some people think it's part of a movement. Some think it's just a fashion. Some think it has to do with Washington's thirst for power.

Whatever. The point is, a lot of people are drinking less these days.

For the country as a whole, the Distilled Spirits Council reports that from 1973 to 1983 "apparent consumption" of spirits per adult (age 18 and over) actually dropped 11.6 million gallons, while wine consumption rose 28.7 million and beer 11.8 million. Since 1980, spirits consumption has dropped each year, and beer-drinking began to fade in 1982, while wine consumption has risen only slightly.

This year, even wine sales are stagnating, despite a glut of California wines and a rising import market.

The fashion is changing. It is no longer chic to be smashed.

Nationally, the trend is strong enough to worry the liquor industry into producing carbonated fruit-juice-and-wine coolers, low-alcohol beers and even nonalcoholic beers such as the Swiss-made Moussy. Apparently figuring if you can't beat 'em, join 'em, major brewers are donating huge amounts of money to Mothers Against Drunk Driving and other grassroots groups that are a significant reason for the new concern about drinking. Meanwhile, a campaign is on to stop marketing alcohol on radio and television.

"The Liquor Handbook" says the industry has suffered a sales decline for three years in a row. "Most certainly," it reports, "competition from other types of beverages, notably beer and wine, continued to play a part. It is now believed, however, that some new consumer attitudes may be forming, brought about by the barrage of alcohol abuse material."

That would include not only the anti-drunk driving campaigns but also the efforts in some states to raise legal drinking ages and cut bar hours. Some see a "neo-Prohibitionist" movement in the country.

As anyone who has quit drinking recently can tell you, it's not such a big deal anymore. What you drink, and how much, no longer seems to convey a secret signal of social status and manly prowess.

It's not an easy thing to pin down, and official figures on the subject have to be read with great suspicion because there are so many different ways to measure this imprecise phenomenon.

Besides, Washington is a hard-drinking town. To the newcomer, any claim that we are easing up on the booze must seem the most dangerously optimistic kind of delusion.

But talk to people who go to a lot of parties. (Easterners and especially urban Easterners tend to do their drinking at parties, according to that great sourcebook, "American Averages." In the West and South they basically drink at home.)

"We don't see so many drunks at parties anymore," commented one veteran Washington caterer. "And there are more nondrinkers. I'm made to notice that, because the hosts are always concerned when they have one. We're all more aware of the nondrinkers these days. There's always a nonalcoholic punch or Perrier or something."

Of course, at the more exalted levels, the Washington party never has been particularly alcoholic. A longtime observer of the party scene said she hasn't seen a real old-fashioned passed-out drunk at a party for 15 years.

"It's the power, the proximity to power," she added. "They get drunk on power, they don't need drinks."

At policymaking levels it is chic to sip club soda -- or nothing at all -- if you plan to go down in history. It is safe to say that nowhere else in the world do official parties flaunt so much liquor to so few takers. (To be sure, this kind of party, the much-reported Washington Party, is not really a party at all. Half the people you see strolling about, carrying a drink for camouflage, are working. So we can consider it a special case. It is the private parties that seem to be changing.)

Washington area suppliers report a definite switch in recent years to lighter drinking, to wine instead of hard liquor, to soda instead of wine. There is also a trend away from medium-priced brands to premium brands, some find.

"Even the serious drinkers are turning from the standard Scotch blends to single-malt Scotches," one distributor said. Malt Scotch is so much in demand here that the price in Georgetown has zoomed to around $25 a fifth.

Do you realize what this means? We may be on the verge of a fashion revolution. For decades, generations, perhaps forever, you were what you drank and a man was judged by how well he held it. The prime purpose of college was to teach you this skill, and the prime purpose of a frat house date was to get the girl so drunk she would do anything. (That was the theory. In actual fact, what she usually did was vomit.)

Even after college, the conversation of many a young American centered on epic drunks, hangover sagas and tales of superdrinkers who had "lined their stomachs," as the folklore had it, with cream or mineral oil to survive incredible alcohol duels. Gene Tunney, who could hold it indefinitely, was a hero. So was Dylan Thomas, who finally achieved the death he courted by downing 17 straight drinks.

You could literally make a career out of bellying up to the bar. A newspaperman was expected to drink. So was an adman. A housepainter. A fighter pilot. An inventor. New York executives raced to arrive early at their lunch dates so they could squeeze in an extra "while-I-was-waiting" martini. (It was imperative when lunching with a nondrinker, for you couldn't very well order two while he was still sloshing away at his ginger ale.)

And weren't drinks bigger in those days? Didn't they have three-ounce jiggers at the Waldorf? Today many bars are automated, serving one ounce or less. In England one has to order a quadruple to get a decent home-style drink.

You knew something was afoot when people started having kir, a sweetish mix of white wine and cassis, and the magazine ads promoted sherry on the rocks to make it acceptable to men. What the industrial-strength drinkers called "kid drinks" began to appear: soda-fountain confections of sweet liqueurs and cream, more apt to give you diabetes than cirrhosis.

You think I'm exaggerating? Would you believe the Haagen-Dazs ice cream people are now marketing a Haagen-Dazs Creme Liqueur?

For Jerry Croce, who runs Lansdowne Catering with his partner, Barry Morgenstern, the new pattern is clear.

"We used to figure a half-bottle of wine per person when ordering for a party," he said. "Now we order at least a case of white wine for every 30 people. That's just for the bar. Not counting wine with the meal. We find that booze is relatively untouched at parties, but the white wine goes."

People are more sophisticated about their wines, too, he added. "They used to drink to get high; now -- except for the very young, who are still into drinking for status -- they drink for the taste. There's more experimenting with little-known wines. And the American wines are better. We weren't getting the good California wines here 15 years ago, but now there are improved shipping techniques, pressurized casks and so forth."

Then too, a number of small California wineries, set up perhaps for tax purposes or simply as expensive hobbies within the last three decades, are hitting the Eastern markets.

Croce also notes a resurgence in red wine, doubtless because it is supposed to have fewer calories than white, but also because it offers more complexities of taste and is, in a word, more interesting.

True, the traditional drinkers are still with us, Croce observed. "You get your Southerners who drink only bourbon, and in the diplomatic corps the drink is still Scotch. Middle-aged professional people tend to stick with the usual, and you find pockets of them at all sorts of parties. Like Uncle Louis at the bar mitzvah who has to have his Crown Royal."

There are always surprises. At one Christmas cocktail party for service personnel, the hosts advised that they would probably need two cases of wine for the 30 guests. Unconvinced, Croce bought only one case. When the party was over he found he had used exactly one bottle of wine. Everyone else drank Scotch or gin.

"Drunks? Not so much anymore. Sometimes the host gives us the word in advance and arranges to have vodka or Scotch on hand under the stairs for special people. But we don't often see anyone falling-down drunk anymore. Generally, people control themselves."

Most interesting to Croce and Morgenstern is the new attitude of hosts, who seem concerned about getting their guests home safely. Some recent court cases holding hosts responsible in guests' accidents have been duly noted, they say.

"Some hosts want the first drink to be strong, especially when there are disparate groups at the party, but then weaken them after that. You rarely see people trying to make somebody drink."

Not so long ago, the nondrinker at a party could expect a certain amount of hazing, cajoling and kidding. There were even those who would try to convince a recovering alcoholic that one or two wouldn't hurt. Today, so many body-conscious people drink club soda that nobody pays much attention.

The pressure to drink at lunch has eased even more dramatically. Outside of the hard-core two-martini group, which appears to be related to a certain socioeconomic stratum of middle-aged men, lunchtime drinkers are becoming almost a novelty around town. Wine spritzers are popular in summer, along with the single lite beer, but many a lunch features nothing stronger than iced tea.

Measuring exactly how much people drink is tricky, for drinks may be left unfinished. Tracking beverage sales and using surveys based on self-reporting are the standard methods, but of course these bring in other factors, such as recessions and inaccurate reporting for one reason or another.

Still, Washington does love its wine. In 1982, according to federal statistics, the District of Columbia drank more wine than any state. We quaffed 6.78 gallons of wine per capita (all ages), with Nevada a distant second at 4.77 and California third with 4.45. At the low end were Arkansas, Kentucky and Mississippi. The national average was 2.21 gallons.

It is true that, as the National Institute on Alcohol Abuse and Alcoholism observes, "residents of popular tourist and convention cities and communities adjacent to 'dry' areas or to states with higher alcohol taxes are likely to be assigned artificially high rates of alcohol consumption."

You might like to know that three out of four adult Americans drink, and half the adults drink beer, according to "American Averages," which also points out that the average American today drinks only half as much as the typical American drank in 1850.

And this nugget: Although we drink 5.8 liters of 100-proof alcohol per person per year, in a drinking Olympics we would win only a bronze medal, because Poland drinks 6.8 liters and the Soviet Union would take the gold with 14.8 liters for every man, woman and child in a year.

Any way you look at it, that's a staggering figure.