Los Angeles — Jesse Jackson claims he's being gypped. Gary Hart says the system is clearly unfair. But Walter Mondale just smiles. What's the fuss? It's over the way Democrats have apportioned delegates to this year's national convention. They've used a hodge-podge system that sometimes favors one candidate, sometimes another - but which now is raising charges that Mr. Mondale has gotten more than his share.
California, which votes today, could bring fresh cries of protest. This state has one of the most unusual systems of all, a system that could trigger arguments over who really won, and who lost, the biggest state of all.
Unlike other states, there is no ''beauty contest'' in the California primary. There is no place on the ballot where voters can simply choose between Mr. Mondale, Mr. Hart, and the Rev. Mr. Jackson.
A second unusual feature is that the state is divided into its 45 congressional districts for the presidential primary. Each district is a separate little contest, a separate race, which will have its winner and its losers.
Third, the rules require a winner-take-all system. If Mondale, Jackson, or Hart gets the most votes in a particular district, he gets all the delegates from that district, not just the majority of them.
There is one final twist. Some districts get more delegates than others. So it's more important to win in Los Angeles (where the 28th District gets eight delegates) than in Sacramento (where the 3rd District gets only four delegates).
Both Hart and Jackson blame Mondale and his allies for setting up such complicated - and they say, unjust - rules around the country. At Sunday night's final presidential debate, the rules became one of the main points of contention between the candidates.
''In a democracy, the people determine delegates, not the rulemakers from the top down,'' complained Jackson. ''I do intend to fight for my share.''
Hart observed: ''It may turn out (after Tuesday's vote) that I have won more primaries, more caucus states, have at least an equal number of votes, if not more popular votes than Mr. Mondale, and not have the same number of delegates. Those are not fair rules.''
Mondale responds that the party rules are as generous to all candidates this year as they have ever been.
Some of the rules admittedly do make it harder for little known or poorly financed challengers, such as Hart and Jackson. These rules, which were backed by Mondale and his allies, bunched primaries together on a hurry-up schedule that favored someone like Mondale and made it harder for long-shot candidates to challenge him.
California's rules, however, aren't really a product of the Mondale campaign. They were written to favor the candidacy of Alan Cranston, this state's senior senator. Mr. Cranston, of course, dropped out of the presidential race after the New Hampshire primary. But his rules linger on.
Jackson and Hart note that because of the rules in earlier primaries, Mondale has won about 51 percent of the delegates so far, even though he's collected only about 38.5 percent of the vote.
Jackson, with 21 percent of the vote, has less than 10 percent of the delegates.
Here in California, the ratio of votes to delegates may again be skewed. Political experts have been poring over the demographics of each district, trying to judge the effects of this year's rules.
In the 28th and 29th Districts (both Los Angeles), Jackson is favored. That means he should get all 16 delegates from those districts.
Hart is favored in the San Francisco area, such as the 6th District that includes Marin, Sonoma, and Solano Counties. Mondale is favored in such areas as the 15th, 17th, and 18th Districts around Fresno.
When it is all added up, a number of analysts say Jackson probably will wind up with less than his ''share'' of delegates, Mondale with more, and Hart will fall somewhere in between. Jackson's problem here appears to be that his greatest strength - California's black voters - is concentrated in small geographical areas.
Mondale's support, on the other hand, appears to be distributed in a way that should result in a maximum number of delegates.
One final point: California's rules allow ticket-splitting. So in San Francisco's 5th District, for example, a voter could select two Mondale delegates, three Hart delegates, and one pledged to Jackson.
Experts say it's not likely. But it is allowed - and it could make it even harder to tell who won, and who lost.