As the fallout settles over Manila from the assassination of Benigno Aquino, a clearer picture of an intense struggle for succession to the presidency is coming into view.
Most political observers, diplomats, and even legal opposition leaders recognize that the major protagonists in the power struggle are themselves loyalists of Ferdinand Marcos who are split into two rival camps, each with support from factions of the military.
The consensus of observers in Manila is that the faction most likely to take power after Marcos is the tandem of his powerful wife, Imelda, or General Fabian Ver, chief of staff of the armed forces.
Mrs. Marcos said Sept. 11 she is so upset over Western press speculation about her political ambitions that she was thinking of resigning her government posts and not running in next year's election for the National Assembly. She now occupies a seat in the assembly, holds a cabinet post as minister of human settlements, and is governor of Metro Manila.
Her statement meets with skepticism since, on previous occasions, Mrs. Marcos backed away from political involvement only to permit herself to ride a ''groundswell'' of support to accept a new post.
As a close ally of Mrs. Marcos, General Ver has emerged in the past several years with considerable power. Since Marcos was first elected president in 1965, Ver has been responsible for the President's personal security force. In 1981 he became the chief of staff of the armed forces. He also heads the National Intelligence Security Agency and the elite Metrocom (a police-intelligence force).
Six weeks ago, he was given command of the Philippine Constabulary, a paramilitary formerly led by Gen. Fidel Ramos.
A conspicuous example of Marcos's confidence in Ver showed up last year when President and Mrs. Marcos visited Saudi Arabia. Marcos left instructions with General Ver about what to do in case an accident befell him. At that time, both Defense Minister Juan Ponce Enrile and Prime Minister Cesar Virata were in Manila.
The second group of contenders in the current power game is said to be led by Defense Minister Enrile who is believed to be supported by General Ramos, now vice chief of staff of the armed forces. Recent events indicate that this group is losing ground. Enrile reportedly has offered his resignation from the cabinet post he has been holding for 15 years, though Marcos reportedly has refused it, as he has on several previous occasions. Moreover, General Ramos's military career has not fared well in recent weeks. At the ceremony Aug. 1 celebrating the anniversary of the Philippine Constabulary which Ramos headed for over a decade, Marcos declared that control of the constabulary and the Integrated National Police are under Ver.
Another figure who has until now kept a low profile but whose name constantly crops up in discussions of the power game is Eduardo M. Cojuangco Jr., a rich businessman who has virtual control of the nation's coconut industry. Coconuts are the Philippines' top export earner and Conjuangco is president of United Coconut Planters Bank in Manila. At one time Conjuangco was thought to be a close ally fo Defense Secretary Enrile, but reliable sources say that he has started detaching himself from the Enrile bloc.
There is growing expectation that if the scheduled presidential election in 1987 materializes, Cojuangco could be a major contender and would have Marcos's support.
In spite of the political jockeying, the Philippine Constitution provides that in the event Marcos passes from the scene, the president's successor will be an 11-member executive committee, composed of top cabinet members headed by Prime Minister Virata and including Mrs. Marcos. The committee is supposed to run the government until a presidential election is held.
Several days before Aquino left Boston for Manila, he stated he could help dissipate a power struggle because ''Mr. Marcos is a Filipino.'' He believed he could appeal to Marcos's conscience to ''restore to us our democratic freedoms which he took from us'' when he declared martial law in 1972.
The moderate opposition to Marcos is in disarray. The death of Aquino, the only opposition leader who had the popular stature and political acuteness to unite the splintered legal opposition, has left the moderates with no leverage as the succession race heats up.
Since the moderate opposition appears to have no replacement for Aquino, it is often said that his assassination means the radicalization of Philippine politics. The radical leftists, however, do not seem to be in a hurry to move in to recruit the moderates to their side.
''The brutality and senselessness not only of the Aquino murder but of other government and military acts will make the youthful moderates more receptive to leftist politics,'' said a member of National Democratic Front, a coalition of radical and nationalist organizations, such as the outlawed Communist Party of the Philippines.
The radicalization of Philippine politics will therefore depend on how the government will deal with dissent from now on. If it continues to be repressive, it could speed up the flow of moderates into the radicals' camp.