The shame of the Republicans in Tuesday's California primary was not only their lost chance for a fair share of state and national power but their listless, maladroit fight to achieve it.

The two ballot proposals to end Democratic gerrymandering of both the legislature and congressional delegation, Propositions 118 and 119, lost badly. No surprise, since Republicans were outspent better than 5-to-1 and outorganized by even more. Chances of electing a Republican governor who would battle gerrymandering faded when Democrats nominated Dianne Feinstein, the radiant ex-mayor of San Francisco. Her election would leave only appeal to the courts -- a tortuous, uncertain remedy.

This was clearly foreseen a month before the primary by operatives of both parties, including a puzzled Mickey Kantor. The prominent Los Angeles Democrat told us he was perplexed ''because reapportionment here means so much to the Republicans nationally, and they aren't doing anything about it.'' After the voters spoke Tuesday, Kantor told us: ''I still can't understand it.''

Nor can many Republicans, though the fiasco derives from familiar sources of party trouble. The return of ideological factionalism finds Republicans here more eager to combat each other than Democrats. Party leaders are more attuned to selfish interests. Supposedly Republican corporation executives pour out money to sustain the Democratic-dominated status quo. Summed up, the Grand Old Party is far from ready for national leadership.

Arithmetic reveals the stakes. With the two parties evenly divided, Democrats hold about 60 percent of both the state legislature and the congressional delegation thanks to the gerrymandering artistry after the 1980 census by the late Rep. Phil Burton.

The 1990 census makes the pot richer because of the state's population growth: a possible seven-seat pickup in the House to a total 52 out of 435. All hopes for Republican control of the House before the year 2000 depend on fair redistricting in California. If they got it, Republicans would pick up an additional 15 to 20 congressional seats in the 1992 elections.

Republican National Chairman Lee Atwater understood this, and on several trips west pledged to lead the charge. So, California GOP activists now unconscionably blame Atwater's illness for their own failures.

No Golden State Republican wanted to carry the flag. Retiring Gov. George Deukmejian's inaction is attributed by friends to his fight for a failed reapportionment initiative in 1984. Sen. Pete Wilson's lack of interest is blamed by cynics on his desire to make his election as governor the party's only hope for fair apportionment. Wilson men deny that, saying his hands were full during the primary season backing an anti-crime ballot proposition. Without question, the Wilson-dominated state party apparatus was not geared up for reapportionment.

The two rival ballot initiatives facing confused voters reflected deep divisions in the California GOP. The noxious feud between conservative legislative leaders and the moderate forces of Rep. Bill Thomas overrode even this issue, choosing sides between the issues. Proposition 118 would have prohibited gerrymander while retaining power for the legislature; Proposition 119 would have delegated redistricting to a judge-appointed commission.

Management of the campaign by the Dolphin Group, a political consulting firm with mixed success recently, was money-starved and unimaginative. Charlton Heston had to volunteer to cut a commercial in response to liberal actors attacking redistricting.

Heston's impact was swamped by TV spots financed with over $5 million raised by Speaker Willie Brown and State Senate President David Roberti. With redistricting a challenge to his status as the state's single most powerful figure, Brown had two aims: kill the two propositions and defeat state Attorney General John Van de Kamp, the party-endorsed candidate for governor who wants to limit legislative terms. He accomplished both.

The ample war chest enabled TV-watchers to hear Jack Lemmon and James Garner warn of special interests poised to pollute the environment if the propositions passed. That tickled lobbyists who, at Speaker Brown's behest, collected bushels of bucks from big business, particularly oil, to defeat the reforms.

The corporate chiefs are mainly Republicans, but since they have to live with Willie Brown, they were not about to offend him by listing their names as backers of the two propositions. That was an easy cop-out, given a Republican leadership preoccupied by personal ambition and rivalry and not yet ready to take full national power.