SISON, PHILIPPINES -- When president Ferdinand Marcos was toppled in a "people power" uprising four years ago, his closest business associate here, Eduardo "Danding" Cojuangco, remembers driving to the airport in fear of his life, terrified that the crowds thronging Manila's streets might recognize him and take revenge.

Now, six months after returning home from exile in Los Angeles despite a travel ban against him, Cojuangco appears to be consolidating the remnants of Marcos's political machine and positioning himself as the most formidable presidential contender for 1992 elections, in the view of many politicians and other analysts.

Spicing up the political brew is Cojuangco's relationship to President Corazon Aquino; they are estranged cousins, setting the stage for the next election to become a family feud if Aquino decides to run, as some analysts suspect, or if she openly backs another candidate, such as her loyal defense secretary, Fidel Ramos.

Cojuangco, said to have a fortune of nearly half a billion dollars, has been able to eclipse other opposition candidates despite major legal troubles. There are at least 20 political corruption cases pending against him, and the government has accused him of providing much of the financing for the December coup bid that nearly toppled Aquino, although no evidence has been presented. Just last week, he was forced to pay bail when an arrest warrant was issued against him in an old case charging him with being a frontman for Marcos in a newspaper takeover.

"He's a very impressive politician," said a Western diplomat here who has been watching Cojuangco. "He's either going to be the next president, or the person who decides who the next president will be."

When Marcos was toppled, Cojuangco joined him in exile in the United States, his passport revoked by the Aquino government. Somehow, a week before the December coup bid, he returned home with what he insisted was a valid passport, and has been active ever since.

Cojuangco, widely known here as "the boss," has met with more than a hundred congressmen and numerous mayors and local officials, assessing his support and reminding potential backers of the Filipino traditions of loyalty and obligation.

He has also held several off-the-record sessions with journalists and has traveled around the archipelago, from Marcos's heartland of Ilocos in the far north to the southernmost island of Mindanao, where Cojuangco still has considerable business interests.

While there are no reliable nationwide public opinion polls in the Philippines, politicians and Western diplomatic analysts here say that Aquino's political troubles -- and the perception that her presidency is weak -- play into the hands of Cojuangco, who has cultivated the image of a Marcos-style political "strong man" who can get things done. Many local politicians appear to be searching for a new post-Aquino political patron, a charismatic figure to associate with before mounting their own reelection bids in 1992.

Cojuangco in the past essentially eschewed the political spotlight, but he did serve as a congressman and governor from his native province, Tarlac, where he is still fondly remembered by farmers for voluntarily turning over half of his land holdings for redistribution to peasant farmers.

"If he throws his hat into the ring, he could be the most formidable candidate because he has a machine in place," said Francisco Tatad, a newspaper editor and publisher and an opposition candidate for Senate in 1987. "He doesn't have supporters, he has followers."

Analysts see Cojuangco's close association with the Marcos regime as his most serious obstacle to a presidential bid. Perhaps realizing this, he used a recent lavish birthday celebration with 20,000 guests, effectively a political "coming out" party, to make his final public break with Marcos, who died in Honolulu last September.

Attending the bash at an estate Cojuangco owns in northern Pangasinan Province were some prominent anti-Aquino politicians and many of his supporters, some of whom wore "Danding For President" headbands and T-shirts proclaiming "Danding Forever," and "It's a Bird! It's a Plane! . . . No, It's Danding!"

In a birthday address that sounded more like a political speech, Cojuangco defended his decision to join Marcos in exile. "I will remember him always as my friend," he said, "and I will never disgrace his memory for the rest of my days . . . . {But} let us go on with our lives. Let us bury the past and move on to a new beginning," he said, before launching into a blistering attack on the Aquino government.

Dick Gordon, the mayor of Olongapo City and an unabashed Cojuangco supporter, said Cojuangco "closed the book on Marcos in his speech."

By keeping loyal to Marcos until his death, Gordon and other political analysts said, Cojuangco is now in a good position to win the support of the nine Ilocano provinces that make up Luzon Island's so-called "solid north," Marcos's political base. Cojuangco is also a fluent Ilocano speaker, an asset in a region known for its clannishness.

Despite all this, political observers and opposition leaders said Cojuangco was unlikely to run for president under the banner of Marcos's old party, the KBL, which has become discredited.

Rather, they said, Cojuangco would likely bring together parts of the KBL and elements of the opposition Nacionalista Party -- and may even be able to woo some supporters from the ruling party in Congress, the LDP.

Before formally entering the presidential race, however, Cojuangco must contend with the corruption cases against him, all of them stemming from his business dealings under Marcos's rule. The most serious involve allegations that he used a controversial, government-imposed levy on coconut farmers from 1972 to 1986 to finance his own private business ventures.

Cojuangco's lawyers maintain that they can win if they ever have their day in court -- but given the Philippines' inefficient judicial system, the cases are unlikely to reach a courtroom before the 1992 elections are held. Furthermore, said lawyer Estelito Mendoza, despite the barrage of civil and criminal cases, the government has not accused Cojuangco of plundering the nation's wealth to salt money away overseas.

"This could be advantageous if the people see these cases are no more than a campaign of persecution," Mendoza said. "People like an underdog."

As for a possible race pitting Cojuangco against his cousin, the president, observers say it is possible.

Aquino has repeatedly said she would not be a candidate in 1992, but speculation increased that she was getting ready to launch a reelection bid when she announced the formation last week of a new political movement called "Linking Arms."

Some diplomatic analysts have said Aquino might seek reelection if supporters can convince her that she is the only person capable of blocking Cojuangco from the presidency.