CHINA'S Communist Party has celebrated its 70th anniversary with a combative pledge to turn back the democratic tide that has swept away all but a handful of the world's communist regimes.In a speech published July 2 in official newspapers, party General Secretary Jiang Zemin warned of subversion from without and decay from within and portrayed the party's future as primarily a struggle for survival. Mr. Jiang avoided mentioning controversial and sometimes brutal party actions that have progressively alienated Chinese citizens for more than three decades. Instead, in a tacit admission of the party's shaky record, he sought to rally Chinese by recalling the achievements of the party before it came to power. The speech and other July 1 anniversary events underscored how the party leadership today binds China to a brittle kind of order, with ruler and ruled distant and tense, say Western diplomats and Chinese dissidents. At one anniversary party, workers wearing tight slacks, mini-skirts, and other trappings of "bourgeois decadence" sat with glazed eyes through classic party anthems but leapt to their feet and danced to disco tunes from Hong Kong. Two years after the suppression of pro-democracy protests in Beijing, many Chinese say that party ideology is still irrelevant to their lives. Intellectuals in particular chafe at the leadership's militant refusal to carry out political liberalization. Anniversary events affirmed party leaders' intolerance of dissent and the idea of an institutionalized challenge to their monopoly on power. If the party were pushed aside in a multiparty system, "the people's political power would be lost, the socialist system subverted, the country split, and the people subjected to suffering," Jiang maintained. Ironically, it is through openness and pluralism that the party could best eradicate corruption and take the other steps necessary to ensure its longevity, say the Western diplomats and Chinese dissidents. The party's corrosive elitism was particularly conspicuous at a Beijing dinner Saturday, said one party member: Cadres at the self-congratulatory banquet battened on a lavish spread of food even though, by the party's own reckoning, millions of citizens remain poorly fed and clothed, he said on condition of anonymity. Most glaringly, however, Jiang and other party stalwarts repeatedly hailed the party as if oblivious to signs that it has lost the hearts and minds of the people it rules. "Our party has proved to be a great, glorious, and correct party," Jiang said in the speech broadcast nationwide on July 1. Showered by party propaganda recasting reality, intellectuals privately lampoon the Three Good Styles for governing, a motto coined during the revolution. From a cave in the desolate hills of Yan'an, Mao Zedong called on the party to "link theory with practice, keep close ties with the masses, and practice criticism and self-criticism." But today, according to the popular quip, the approach of the party's 50.32 million members is: "Link theory with profit, keep close ties with the leaders, and praise yourself and others." Jiang acknowledged that corruption poses a dire threat to the party. "If these decadent phenomena are allowed to continue, the party will be doomed to self-destruction," he said. Public anger over graft was a major cause of the massive protests for liberal change in the spring of 1989. In an update to the longstanding campaign against corruption, the party recently announced that since 1989, it had disciplined 328,000 members, ejecting 127,000 of them. But leaders say the biggest menace to party power lies abroad: "Hostile foreign forces" conspire to goad China toward capitalism and democracy. "Decadent capitalist ideas, values, and ways of life will unavoidably take advantage of our weak points to break in and contaminate the body of our party," Jiang said.