THE leaders who plunged Cambodia into more than two decades of war and turmoil are nudging the country toward a postwar contest for political survival.The return of Prince Norodom Sihanouk has thrown Cambodia into flux, catapulting the former king to the forefront as restored head of state, triggering political shifts, and isolating the militarily powerful Khmer Rouge. No one is sure if the new round of intrigue will lead this impoverished country into new tumult or forge some desperately needed political stability, analysts say. "There remains a deep suspicion and mistrust among all the factions," says a Western diplomat. "Still, there's a lot of hearts-and-minds winning that will go on. A positive aspect is that you have a population which is thoroughly sick of war and ready to give it a chance." For the moment, Sihanouk is on center stage. Within days of arriving in his faded royal capital, the erstwhile monarch shed his decade-long alliance with Cambodia's rebels, including the Khmer Rouge, and blessed a new coalition between his son, Prince Norodom Ranariddh, and Phnom Penh Prime Minister Hun Sen, whom Sihanouk once condemned. In another move to bolster his clout, observers said, the temperamental leader insisted on being redesignated Cambodia's head of state. Ousted in 1970 by a United States-backed coup, Sihanouk also remains the head of the Supreme National Council (SNC), an interim reconciliation body comprised of the four rival factions. "I don't pretend to be the best chief of state," Sihanouk told a press conference, "but I pretend to be the least bad chief of state." Some Western and Cambodian political observers see in these recent moves the Sihanouk of old: a mercurial autocrat with little tolerance for having his authority challenged. That arrogance, in part, fed the rise to power of Khmer Rouge communists who killed at least 1 million Cambodians during a four-year-rule in the 1970s. "Sihanouk wants to stay neutral as president of the SNC," says an international aid worker who spent several years in Phnom Penh. "But he also wants to be the sole architect of the Cambodian peace." And yet to many young Cambodians, Sihanouk is merely a name. Half of the 350,000 Cambodians living in refugee camps on the Thai border are too young to remember the former god-king's rule. Those who remained in the country are drawn more to Hun Sen, Phnom Penh's prime minister. Forty-year-old Srean Sang stood on a street corner to watch the former king's arrival with her elderly aunt. But it didn't mean much, she said. "I know Hun Sen better," she said, looking at a flattering portrait of Sihanouk in his youth. Indeed, popular among urbanites and intellectuals, Hun Sen rides on Sihanouk's coattails even as he offers the long absent leader a political base. Hun Sun, a former Khmer Rouge officer who defected to Vietnam in 1977 and became part of a new government installed by the invading Vietnamese, has moved to distance himself from his past. Hun Sen's ruling party abandoned communism last month and pledged support for multiparty democracy. Yet the youthful politician remains under the thumb of committed communist Chea Sim, who controls the party's grass roots network and in the past has wielded power oppresively, imprisoning scores of dissidents and political allies of Hun Sen. Recently, in the wake of the peace agreement, Phnom Penh said it released more than 1,000 political prisoners and prisoners of war. Still, despite the ruling communists' new liberal policies, observers say the capital remains tense. "The situation is so fragile," a dissident says. "This is not the right time for setting up a new political party." Surrounded by corrupt officials and family members, Hun Sen also remains vulnerable on his government's sullied image. Since the signing of the Oct. 23 peace accord, former eastern bloc diplomats in Phnom Penh say corruption within the increasingly insecure regime has spread. To counter official corruption and the growing gap between the urban well-to-do and the rural poor, Western diplomats and aid workers say development has become the new political battleground in Cambodia. "Most of this country's political thoughts come out of the stomach rather than the head," observes a UN official. Even the US appears to be abandoning its support for the right-wing faction of former Prime Minister Son Sann and shifting support to former foes, Sihanouk and Hun Sen. But Lawrence Twining, head of the new US delegation in Phnom Penh recently received a lecture from Sihanouk: "Your money should not go to the pockets of officials and civil servants, but your wealth should help the people." Political analysts question whether Sihanouk and his new political allies can counter corruption and poverty and keep the Khmer Rouge at bay. Even Ta Mok, a brutal guerrilla leader and the second most powerful after the Khmer Rouge's Pol Pot, is savvily changing his approach, building hospitals, schools, roads, and pagodas to attract support of rural Cambodians, Western analysts say. "Ta Mok is a rural conservative who doesn't like urban development," says an observer. "His strategy is a paradox because the modern world is the enemy to him." Retaining links with the Phnom Penh leaders, most of whom are former Khmer Rouge members, the guerrillas could still reestablish ties with Chea Sim and other hard-liners in the capital and forge a new communist coalition in Cambodia, some observers note. "What has been solved is the international dimensions of the Cambodian problem," says an international aid official. "The real problems are still down the road."