The hope that computer technology will save the Democratic Party, as claimed by newly elected National Chairman Charles T. Manatt, looked forlorn Feb. 26 when Manatt, suddenly confronted by what has ravaged his party the past decade, blinked.

Mayor Richard Hatcher of Gary, Ind., leader of the black caucus, threatened a black walkout from the Democratic National Committee meeting unless his demands were met. That continued a decade of "mau-mauing" by black Democrats claiming "racism." But something new was added: what appeared to be anti-Semitic overtones weakening the flimsy bonds holding the Democratic coalition together.

When Manatt did not tell Hatcher to go ahead and walk, he perpetuated his party as a loose confederation of mutually hostile caucuses of blacks, women, Jews, Hispanics and others. Computers were cited by Manatt in his successful campaign for chairman as the answer to Republican superiority in fund-raising and campaign organization. But what ails the Democrats cannot be cured by computers.

What ails the Democrats stems from the quota system started in 1972. Democratic politicians now regard themselves as caucus members first, party members second. So divided, they have trouble focusing on a unified Democratic response to Reaganism.

Dick Hatcher, soft-spoken and urbane, has been part of the problem since his election as mayor of Gary in 1967 at age 33. In 1974, at the Democratic Party's first midterm convention in Kansas City, he branded an anti-quota provision in the party charter as "racist." If not removed, said Hatcher, blacks will walk out. Althoughh then-national chairman Robert Strauss wanted to call his bluff and risk the consequences, other party leaders did not. They forced a surrender.

More than six years later in Manatt's suite at the Sheraton-Washington Hotel, Hatcher was back at the old stand. He had just ousted Detroit's Mayor Coleman Young as chairman of the black caucus and was demanding that 10 blacks be kept as at-large members of the national committee; Young had accepted eight so that Manatt could add two labor members.

What's more, Hatcher had fingered two specific at-large candidates to be replaced by blacks: former state chairman Ann Campbell of New Jersey and Mark Siegel of Maryland, formerly executive director of the national committee. Both are indisputably liberals. Siegel supported Sen. Edward Kennedy last year; Campbell's credentials go back to George McGovern in 1972.

Their sin appears to have been opposition to quotas. In the meeting with Manatt, Hatcher called Siegel a "racist." Besides, the mayor made clear, he could not support anybody who quit Jimmy Carter's White House staff out of support for Israel, as Siegel had. Hatcher and his blacks would walk out if they did not get their way.

Manatt might have been justified in telling the mayor to be gone, after informing him that Jewish-black fratricide had no place in the party of the New Deal. But that is not the way of today's Democratic leaders and certainly not of Chuck Manatt.

Born and reared in Iowa and now a self-made millionaire lawyer-banker in Los Angeles at age 45, Manatt abhors confrontational politics. Elected California state Democratic chairman in 1971 as a non-ideological technician, he has survived in the maelstrom of California and national politics by coolly avoiding intraparty warfare and promoting conciliation. On the eve of his greatest political triumph, Manatt was not about to deviate from form.

He approached Siegel, who was working the floor for him at the committee meeting, with this proposition: Would he and Campbell withdraw their candidates today if appointed slots on the committee could be found for them tomorrow? Under no conditions, Siegel replied; if he withdrew today, there would be no tomorrow.

Other voices in the party angrily intervened. Georgia's state Chairman Marjorie Thurman warned that 55 state chairmen would walk out if Campbell and Siegel were thrown overboard. AFL-CIO officials backed her. Teddy Kennedy risked black wrath by telephoning committee members in Siegel's behalf. So Hatcher was promised his two black seats the next day by appointment, and he did not walk.

"Dick Hatcher's just not a team player, not a party man," one Democratic old pro explained to us. Why, then, on Feb. 27 was he elected deputy chairman of the Democratic National Committee? Why is that deputy chairmanship reserved for blacks as two others are reserved for Hispanics and women? What good do all these special causes do for the party? h

Few Democrats question these intricate arrangements not even dreamed of a decade ago. Manatt does not ask. When he let Mayor Hatcher's attack on Siegel go unanswered, the new chairman showed no stomach for turning a loose confederation of caucuses into a working coalition capable of national leadership.