THE real-life soap opera involving the Philippines' most powerful families once again clouds a troubled political future.The anticipated homecoming today of the former first lady, Imelda Marcos, is expected to touch off a new tug-of-war with her widowed rival, President Corazon Aquino, and could cap three decades of bitter rivalry between domineering political dynasties. The return of the flamboyant widow of the late President Ferdinand Marcos stirs a political scene already seething in economic crisis, uneasiness over the expected closing of United States military bases, and doubts about the future role of the powerful military. In what many observers see as political mischief-making, Mrs. Marcos has raised the level of confusion over whether she will return with her husband's body and in her New York press conferences has hinted at running for president next year if she can outlast an array of tax-evasion charges filed by the government. Marcos died in 1989 in Hawaii where he fled after being overthrown in a popular revolution that led to Mrs. Aquino's rise to power. Aquino blames the Marcoses for the assassination of her husband, opposition leader Benigno Aquino, in 1983 and for looting the country of billions of dollars during two decades in power. The return and trial of Mrs. Marcos could clear the way for recouping some of the funds. Hoping to avoid political unrest in the capital, Manila, Aquino says Marcos' body can only be flown directly from Hawaii to his birthplace in northern Luzon island for burial. The confrontation between Marcos and Aquino is already churning the country's politics. Eduardo "Danding" Cojuangco, a loyalist of the late President Marcos and a cousin of Aquino, has launched a bid to lead Aquino's opposition in next year's presidential election and outmaneuver Marcos or other rivals within the right-wing Nacionalista Party. Also vying for the party leadership are Vice President Salvador Laurel, scion of a longtime political family, and Sen. Juan Ponce Enrile, a one-time Cabinet minister of Marcos, who was frequently at odds with the ambitious Imelda when she shared the apogee of Philippine power with her husband. Although Marcos is expected to receive a tumultuous welcome, analysts are mixed about her overall political impact. Widely blamed for the excess of the Marcos years, Imelda's presence could split Marcos loyalists, observers say. As a political force in her own right, some analysts say, her effect will be minimal. As new political forces and faces appear in provinces such as Mindinao, Negros, and Cebu, the old rivalries will fade, says Amando Doronila, a prominent Manila newspaper editor. "The old families are there, but there are also a lot of new people in politics." While in exile, however, she built her own political contacts and, as Marcos' widow, can play on loyalties and debts to her late husband. Her legendary fortune, believed to be stashed away overseas, will make her an important political force, observers say. Blas Ople, a former Marcos Cabinet minister insists Imelda is still a power broker within the Nacionalista party. "Her political worth is more than her money," he maintains. Imelda's presence may also force Aquino, a former housewife who was thrust into politics by her husband's death, to rethink her decision not to seek reelection. Already, Aquino is under pressure from her brother, Congressman Jose "Peping" Cojuangco, who has been at odds with his ambitious cousin, Eduardo, and other family members, to run again in the presidential election next May. Pressure for Aquino's reelection has stirred fears of a new coup attempt by military rebels as the armed forces leadership tries to negotiate a surrender of fugitive dissidents. Aquino has survived seven coup attempts since 1986.