President Aquino faces toughest test yet of her survival skills. Any opposition move against her is most likely in the next few weeks

Philippines President Corazon Aquino has hit the roughest political patch in her short tenure. To survive, she will need all the skills she can muster to balance the polarized groups jockeying for power between now and the Feb 2. plebiscite on the draft constitution.

Last week, Mrs. Aquino allowed the military to step up operations against communist rebels despite progress toward a cease-fire. Her advisers called it ``letting off some steam'' from the newly vocal anticommunist right wing, led by Defense Minister Juan Ponce Enrile.

This week, she allowed leftist groups to ``let off a little steam,'' as she condoned their general strikes in response to the Nov. 13 slaying of leftist labor leader Rolando Olalia.

In power for nearly nine months, Aquino has had to learn to balance the extremely polarized factions resulting from 20 years of rule by Ferdinand Marcos. By doing so, she has kept the important middle-class support that helped her come to power - and can now help her survive the next few potentially hazardous weeks leading up to the crucial plebiscite.

If she rides out this period, her grand strategy will likely survive: win approval of a new constitution, hold local and national elections in May, revive the economy, and keep both the radical left and right off guard in the meantime by maintaining dialogue.

But there are three reasons why this plan is now jeopardized:

First, frustrations are peaking over her inability to get the wheels of government turning fast enough to meet heightened expectations.

Second, cease-fire talks with the communist-led New People's Army (NPA) are nearing final stages. After 17 years of virtual civil war, elements in the military and the NPA find it hard to give up armed conflict, distrusting the other side.

Third, the February plebiscite forces the nation's politicians to decide if they support Aquino or not, since the vote is seen largely as a referendum on the provision in the proposed charter that grants Aquino and Vice-President Salvador Laurel their posts until 1992.

If a group of politicians wished to bring the ``provisional'' Aquino government down and take power, this month or next would be the time to do it. A ``yes'' vote on the plebiscite would only strengthen Aquino's authority.

Although Mr. Enrile has cooled down his recent public criticisms of the Aquino government, the right-of-center political parties appear to be unsettled on how boldly to challenge Aquino.

The challenges the President faces stem in part from her unusual approach of tolerance and reconciliation. Deputy Defense Minister Rafael Ileto has said that her forgiveness of the 300 soldiers who took over the Manila Hotel for three days in July showed too much leniency, emboldening other challengers.

The left had the same criticism after the murder by unknown assailants of Olalia, chairman of both the radical union known as May 1st Movement (KMU) and the People's Party, formed recently with the help of formerly jailed communist leaders.

KMU leaders claim the slaying was the ``logical result of the President's indecisiveness and compromising attitude in dealing with the Marcos holdovers, a fact that had emboldened Enrile and his cohorts to plot and freely engage in bloody intrigues.''

KMU and other leftist groups are planning a general work stoppage in Manila today and on the day of Olalia's funeral, planned for Thursday or Friday. KMU claims 500,000 members in the nation's offices and factories, but its numbers may be closer to 200,000.

Calls for such general strikes during the Marcos years failed.

Thus, the left is taking a risk. It already lost crucial middle-class support on Saturday when a major moderate ``cause oriented'' group known as Bandila called for a defusing of ``the tense situation.''

The NPA, in strong language, has held Aquino ``morally responsible'' for the Olalia murder. But the murder helps the rebels gain a better bargaining position when cease-fire talks resume, expected some time after this week's protests.

Both sides in the talks hope to gain the ``moral high ground'' with the public in case the talks collapse or a cease-fire fails.

Aquino sent a message to the rebel negotiators asking them ``not to fall into the trap'' set by those seeking to stop the cease-fire talks.