CALIFORNIA Democrats are going to move the presidential primary from its traditional June date to March 3--only one week after the primary season begins with the New Hampshire primary and Iowa caucuses.

This procedural change means more than a movement on the calendar. California is the most populous state in the nation, meaning it has the most electoral votes. After Congressional districts are redrawn to reflect the results of the 1990 census, California will likely see its representation increased even more.

Since 1968, the June California primary has generally been more a coronation than a real electoral contest. With California voting at the beginning of the season, it will have substantial influence in choosing the party's candidate, instead of just confirming the choice of 48 other states.

MOST national Democrats favor the change because of the capricious nature of Iowa and New Hampshire contests. Relative unknowns could pull off surprise early victories in the unpredictable world of Iowa caucusing, but could be unable to woo the rest of the nation. California's size and variety should favor candidates with more diverse appeal--and more money.

A Democrat who wins California in a contested primary election might garner California's 47 electoral votes in the national election. And an early decisive victory in the Golden State would create a dominant party candidate at an early stage, preempting the intra-party squabbling that has plagued the Democrats in recent campaigns.

LIKE Americans several generations ago, the promise of a new land in the West is attractive, however risky. The risks involve the fact that California has a diverse and occasionally schizophrenic electorate. California includes progressive San Francisco and conservative Orange County. It was the birthplace of some of the strictest pollution-control laws in the nation, as well as the populist tax revolt Proposition 13. It claims both Jerry Brown and Ronald Reagan as governors.

Indeed, Republicans might benefit just as much as Democrats if California picks the winner. California might choose a favorite son (liberal Senator Alan Cranston, for example) who doesn't appeal to the rest of the nation.

Regardless of whom it helps, California's size and links to Hollywood will change the nature of the early primary season. No longer will the candidate being interrogated by an Iowa farmer hold the nation's attention. Stump speeches to Iowa heartlanders and New Hampshire yankees might be more charming, but Morgan Fairchild introducing a candidate at the Century Plaza will certainly be glitzier.

THE hope of Californians is that their importance in the general election is mirrored in the primaries. The hope of Democrats is that California will weed out the national candidate from the parochial ones.

The granola mix of California may not be representative of an entire nation. But neither is the Iowa or New Hampshire, or, for that matter, Texas or Hawaii. The significance of California is not that it is different, but that it is generously and diversely populated. As with Iowa or New Hampshire, a "no" from California will not kill a candidate, but a "yes" will be a much stronger signal of a candidate's viability.

For a party that has lost five of the past six presidential elections, almost any change is worth a try.

Nevertheless, the Democrats should not assume that this procedural change can replace a substantive one. Moving the California primary will not be a panacea for the Democrats.

California cannot expect to offer a fait accompli to the rest of the nation. It can only offer a candidate who is acceptable to a critically important state, a state which chooses to finally be recognized in the primaries.

California may finally help the Democrats pick a national candidate. The Democrats, and politics, are going Pacific Standard Time.