Changing role of four-year party rites. PACKAGING THE DEMOCRATS

IT'S really a coronation, not a convention. Tomorrow night, when the roll call of the states begins - ``Mr. Speaker, Alabama casts 65 votes for ...'' - the outcome of the Democratic National Convention will already be known. Despite some competition from Jesse Jackson, Michael Dukakis will be crowned king of the party.

In an age of democratic primaries and open politics, much of the excitement and mystery has vanished from conventions. No longer are nominees picked in smoke-filled rooms. No longer do floor battles stretch out to 10, 20, or even 100 ballots. Today's conventions are as predictable as a Rambo movie. (Conventions as television spectacles, Page 28.)

Delegates, who once came to conventions uncommitted to anyone, and who owed allegiance only to their state or local parties, today are instruments of the candidates. They are handpicked for loyalty. Were it not for Governor Dukakis, most of the Democratic delegates would not be here.

Some analysts, such as Paul Quirk of the University of Illinois (Chicago), suggest we may be witnessing the gradual demise of national conventions. Aside from cheering their heroes, delegates to these meetings do little of substance.

Yet 4,212 Democratic delegates trooped to Atlanta this week. So did an estimated 13,500 reporters, photographers, commentators, TV cameramen, and technicians.

And despite the predictable plot, more than half the American people are watching the spectacle unfold this week on TV.

``It's tradition and history,'' says political veteran Richard Scammon, who has attended many of these quadrennial rites. ``And it's show business. It's Democrats putting the best face on their party and trying to sell a candidate.''

Indeed, political conventions, which once truly chose candidates, approved party rules, and argued over platforms, are no longer deliberative bodies. Instead, party insiders view conventions as large media productions, geared primarily to preparing the country for the start of the fall campaign.

Conventions can still be hazardous. Remember Chicago, 1968? Riots in the streets left the Democratic standard in shreds, and Hubert Humphrey's hopes in ruins. And New York, 1980? Factional fighting on the floor hurt President Jimmy Carter's reelection chances that year.

Year by year, however, the outcome of conventions has become more certain.

That has given media wizards the opportunity to turn convention halls into large TV studios. Each day is carefully scripted, minute by minute. The goal: Hollywood-style imagery to sell this year's products - Mr. Dukakis and George Bush.

Peter Hart, a Democratic pollster, predicted recently that Dukakis could spring into a 20-point lead over Mr. Bush because of all the hoopla here. But he also warned before this week's Dukakis-Jackson rapprochement:

``The convention could do great damage to the Democrats if things don't go well. Based on what they see, the voters will say, this is a party either ready to govern, or this is a party that's not ready to govern.''

Democrats are aware that this week, Americans are getting their first good look at Dukakis - for good or ill.

Mervin Field, a California pollster, has measured the impact of conventions on many candidates. He remembers 1972, when George McGovern gave his acceptance speech in the early hours of the morning, missed most of the American TV audience, and began his slide toward a crushing defeat. On the other hand, convention excitement in 1984 over Geraldine Ferraro sent Walter Mondale soaring briefly in the polls - the only time he led Ronald Reagan all year.

Mr. Field recalls that in 1976, ``Carter was over 30 points ahead, but when the public got a look [during the convention], he started down. ... Even though the public was ready to get rid of the Republicans because of Watergate, they said: `Hold the phone! Carter may not be the kind of guy I'm looking for.''' Carter barely squeaked by Gerald Ford that fall.

In that sense, the conventions still serve an important purpose, for through them Americans can assess the nature of the parties and the candidates, and form bonds with both.

Norman Ornstein, a scholar with the American Enterprise Institute, says the two major risks for Democrats this week are ``squabbling among themselves'' and ``kowtowing to every special interest to keep from squabbling. That can be just as bad.''

Mr. Hart, the pollster, observes that every convention requires compromises. The success or failure of a convention can be judged on whether those compromises are aimed at groups inside the party, or at critical swing voters looking from outside.

In 1988, Democrats appear to be focusing on the swing voters, which could be a plus for them in the fall campaign.