When Filipinos discuss the perennial question of President Ferdinand Marcos's successor, they usually mention the President's wife, Imelda, ministers like Defense Secretary Juan Ponce-Enrile or Labor Minister Blas Ople, or an institution - the military.
On the face of it, a government run or influenced by the military would break with Filipino tradition. Like its former colonizer, the United States, the Philippines has tended to have a strictly professional and apolitical military establishment.
But, in fact, the tradition has already been broken. Ten years of martial law in the Philippines (September 1972 to January 1981) transformed the military into a major force in social and political life.
Under martial law, military officers ran law courts, local governments, federal agencies, and quite a few companies formerly owned by members of the opposition. Some commanders of the Armed Forces of the Philippines (AFP) joined the inner circle of Marcos confidants and advisers.
They are still there today. Several generals remain probably the President's most trusted aides, while the military continues to be active in areas far removed from the usual purview of soldiers.
It was, for example, a committee of officers which invited some of the country's leading journalists, all of them regular critics of the government, to three- or four-hour dialogues late last year. The journalists say the dialogues in fact bordered on intimidation.
Several factors may make the military a political force to contend with:
* Its size, which almost tripled during martial law. In 1972 the combined forces of the AFP and the paramilitary Philippine Constabulary (PC) stood at 54, 000. Today they number 156,000. Ten years ago they were backed up by a paramilitary force - village-based home defense volunteers - of just 400 men. Today there are more than 60,000 home defense force volunteers throughout the country.
* Its scope. In the Philippines today there are probably only two institutions that spread down to the grass roots throughout the country: the Roman Catholic Church and the military. And in many places the two are at loggerheads. Civilian local government and grass-roots civilian politics have been slow to recover from the enforced inactivity of martial law.
* And its cohesion. There are of course rivalries inside the armed forces: between the various services, or between graduates of the Philippine Military Academy (PMA), the country's West Point, and the reserve officers, whom PMA graduates tend to look down on. Some officers are said to be frustrated by the preference they claim has been given to officers from the President's home province of Ilocos Norte.
But if there are any major political rifts inside the armed forces, they have been well hidden from outside eyes. And their cohesion is all the more striking when compared with Mr. Marcos' civilian supporters in his Movement for a New Society (known as Kilusang Bagong Lipunan or KBL in the national language, Tagalog). They are currently embroiled in a fight over the future of the prime minister, Cesar Virata.
Top military leaders seem totally devoted to the President, but they may not automatically transfer that devotion to a successor - even one handpicked by Marcos.
Two of the most influential military officers are relatives of the President: Gen. Fabian Ver, chief of staff, head of the Presidential Security Command, and director of the National Intelligence Board, is said to be an uncle of the President; the deputy chief of staff and commander of the Philippine Constabulary, Gen. Fidel Ramos, is reportedly a cousin.
Both were part of the small group of men who planned martial law, and both have accrued political power and experience since then. There are, however, signs that General Ver does not see eye to eye with another architect of martial law - and would-be successor to the President - Juan Ponce Enrile.
A source sympathetic to Mr. Enrile says there have been ''several attempts to drive a wedge between the President and Enrile.'' The wedge driver, the source suggested, was General Ver. And, the source continued, although General Ver is only chief of staff, he sometimes bypasses Mr. Enrile on important appointments.
In a recent case, informed sources say, the general went over the defense minister's head to persuade President Marcos to recall retired Gen. Pacifico de Leon to active service to assume an important army position. The decision caused considerable surprise, as the AFP is usually thought to be oversupplied with active-duty generals.
Shortly after the appointment was announced, the country's biggest daily newspaper, the Bulletin Today, reported ''widespread demoralization'' among senior officers following the recall of General de Leon. The author of the report is considered close to Mr. Enrile. General de Leon's appointment quickly became embroiled in further controversy: His son-in-law was arrested and accused of having tried to use the general's name to avoid arrest. And a major government development program the general headed became the target of allegations of corruption and gangland killings. The President faded out of the picture.
Generals Ver and Ramos are reported to get on better with Mrs. Marcos. The First Lady, as she likes to be called, has her own allies in the military, though. Her brother-in-law, General Yap, heads the Army Reserve Command, and she is reported to be seeking her own bright young military men.
''Most of the officer corps may well decide to back Mrs. Marcos or one of the others,'' an observer said, ''but the next time around they will not just be servants and they may want to be kingmakers.
Events in the countryside may also affect future military thinking. Faced with an increase in the activities of the communist New People's Army, the government has recently reorganized the armed forces and committed elite units to the affected areas. In addition, just before the new US-Philippines agreement on military bases was signed earlier this month, Prime Minister Virata reportedly said that a large amount of the new base rental payments would be used to buy up-to-date counterinsurgency equipment. The five-year base agreement provides Manila with a total of $900 million, $400 million earmarked for military purchases.
Officers in anticommunist activities in the field describe themselves as working in tandem with the civilian part of the government. ''Basically we're trying to hold down insurgency to tolerable levels until civilian development programs can bite,'' said Col. Dionisio Tan-Gatue, PC commander in one of the hottest regions of the southern Philippines. Colonel Tan, a PMA graduate, is described by his associates as a protege of Mrs. Marcos.
But what if the civilian side fails to do its bit? Some more junior officers involved in civic action programs - originated by the CIA's Maj. Gen. Edward G. Lansdale in the Philippines during an earlier communist revolt - seem already to be having doubts.
''We have a big job,'' said an officer in an insurgent area. ''We have to make up for years of neglect here.'' Another officer in the same area remarked that ''when we do real civic action - listening to local grievances, for example - we sometimes get the feeling that local officials don't want us around,'' - a broad hint that the officials were the problem rather than the solution.
Some senior officers are, like the President's civilian supporters, sometimes accused of profiting from their new prominence. A Manila magazine claimed recently that an unnamed ''top AFP general'' was one of a number of major government figures who had recently bought expensive real estate in the United States.
In 1979 a group of dissident Manila businessmen claimed that the then chief of staff, Gen. Romeo Espino, had assumed control of 15 commercial companies taken over upon the declaration of martial law. Other unnamed senior officers were recently accused of thwarting an anti-vice drive in Quezon City, Manila's twin city, by acting as ''godfathers'' for the establishments targeted in the campaign.
As for the future, most military officers for the time being are probably undecided. But though they may not often confide their political views to civilians, there seems little doubt that they are watching the political scene carefully. At the end of a long talk, during which a well-educated young officer had given fairly standard issue answers to questions about the military operations, this reporter asked him if the army would ever take power.
''I don't think that's in the cards,'' the officer replied. ''Not at the moment anyway.''