ALL too clearly, the political honeymoon is over for Philippine President Corazon Aquino. She has shown great strength and resourcefulness. But the nation's leadership game - as last week's unfortunate assassination of a leftist political-labor leader underscores - is too often played for keeps. Mrs. Aquino is under no delusions about the difficulty of her task. She is where she is precisely because her husband didn't make it down the steps of an airplane on his own return to the Philippine political setting several years back. Talk of possible coups, real or imagined, continues to reverberate throughout the streets of Manila, spurred on in part by the murder of Rolando Olalia, a leftist labor leader and Aquino backer.
Aquino is correct in seeking to bring the Olalia assailants to justice. She is also on target in reserving judgment, as she has so far done, about exactly who is responsible.
Immediate suspicions center on the military. Many officers harbor deep unease about Aquino's attempts to forge a national reconciliation with communist rebels. The initial impact of the Olalia killing was to drive many rebel leaders underground and raise doubts about future government-insurgent negotiations.
Other groups could also benefit from the assassination. Private vendettas are not uncommon. And hard-liners among the insurgents would rather fight than talk.
Rebels say that in a showdown between Aquino and the military they would support the President. Still, it needs to be remembered that the more successful Aquino is in rejuvenating her hard-pressed society, the less support there is likely to be for the rebels.
Last week's killing was discovered just as Aquino returned from a profitable trip to Japan, in which Japanese officials promised up to $1 billion in assistance and business ventures. Now Japanese investors may hesitate before actually mustering up economic support, to make sure that the economy remains stable. This may also prove true of US investors.
So the murder was most likely a shot across the bow - a grim warning of the test ahead of Aquino's leadership.
Whoever is responsible, one overriding factor stands out: Aquino must steel herself and hang on until February 2. That is when the nation's new constitution goes before the Philippine people for ratification. Once ratified, the present transitional government becomes ``institutionalized.'' New processes will then be in place for an orderly transition of power, if that is necessary. And Aquino herself would be firmly in office until new elections scheduled for 1992.
Meanwhile, she will presumably need to stay as close as possible to military loyalists such as Gen. Fidel Ramos, the Army's chief of staff. And, once the new constitution is ratified, as presumably it will be, she should reaffirm that Defense Minister Juan Ponce Enrile, her principal adversary, continues in office at her discretion - or she should remove him outright.
The US should help by quietly reaffirming its commitment to Philippine democracy and to the Aquino presidency.