For Leonardo Lawian, a subsistence farmer on this southern Philippine island of Mindanao, there is only one issue in next month's election contest between President Ferdinand Marcos and opposition candidate Corazon Aquino.

"The person I want to vote for is the one who is going to save me and my children from misery," Lawian said during a campaign rally in this capital of North Cotabato province. That person, he said, is "Cory" Aquino, but he is not sure just what she will do or how she will do it.

"Ever since President Marcos became president, we've never had any change except for the worse," Lawian said as Aquino addressed a crowd here Friday. "I'm praying to God that with Cory my life will change for the better."

For many supporters of Aquino, it seems, that simple article of faith overshadows the issues that Marcos has tried to inject into the campaign, essentially a fusillade of charges that Aquino is allied with Communist rebels, is weak and politically inexperienced and would usher in a period of instability, perhaps even "civil war," if elected.

With the election less than three weeks away, there is little sign that Marcos' main contention, that a vote for Aquino is a vote for communism, is carrying much weight with the electorate.

"It's time for a change," said a teacher in the city of Davao, when asked why she supported the opposition candidate. "Twenty years is too long," she said, referring to Marcos' time in office. "We don't know what Cory would be like, but we're willing to take the risk."

Indeed, the view that it is simply "time for a change" may be one of the most powerful factors in the election, some political observers say. They point out that before Marcos was elected in 1965, no previous Philippine president had been returned to office for a second four-year term.

Marcos broke the pattern when he was reelected in 1969, then declared martial law before his second and final term was due to expire, changed the constitution to permit reelection indefinitely, and won a new six-year term in 1981 in an election boycotted by the opposition. Now, having ruled longer than all previous presidents combined since independence in 1946, he is seeking a "new mandate" more than a year before his current term is due to end.

While Marcos' repeated attempts to link his opponents with Communist rebels have put Aquino on the defensive, the issue is seen here as having more impact in Washington than among Filipino voters. In part, political observers say, this is because of the skepticism with which many of Marcos' statements are greeted here.

"I don't think people believe in the communist scare," said Edwin Salveron, a former government employe in Kidapawan who now belongs to an independent poll-watching group monitoring the Feb. 7 elections. "That does not hold water here."

Although a growing Communist insurgency is of widespread concern, especially on this strife-torn island that Aquino described last week as a "war zone," the more immediate issues appear to be dissatisfaction with the economic situation, corruption among government officials and military abuses, Salveron said.

Lawian, a father of eight who grows coconuts on about 4 1/2 acres of land seven miles from here, said his main complaint these days is the low price of copra, the coconut product that provides his income. He said it now sells for 1.80 pesos or about 10 cents a kilogram (2.2 pounds), compared to 9 pesos or 50 cents a few years ago. As a result, Lawian said, his income has dropped about fivefold in recent years and now comes to about $166 a year.

While Lawian may be largely a victim of falling commodity prices in the world market, he blames his plight on a monopoly of the Philippine coconut industry that Marcos initiated when he ruled the country under martial law from 1972 to 1981. The monopoly was awarded to Eduardo M. Cojuangco Jr., a close friend of the president and a first cousin of Corazon Aquino from a rival side of the family.

Aquino has pledged to abolish the coconut and other monopolies, which Marcos denies exist.

Another issue close to home for many in the Philippine countryside is military abuses, including the misdeeds of members of the paramilitary Civilian Home Defense Force.

According to Salveron, there is still ill feeling about an incident here three months ago in which a drunken soldier shot a cook for reasons unknown. The military said the cook had tried to grab a soldier's weapon, and witnesses who allegedly disputed that version were afraid to testify. Now, only the victim's mother tries to keep the case alive.

Every night she goes to the place where her son died, lights a candle and leaves flowers.

A more celebrated case, also still unresolved, is the murder last year of an Italian priest, the Rev. Tullio Favali, in the village of Tulunan about 30 miles southwest of here. Eight persons are on trial for the murder, including three members of the locally powerful Manero family, which has connections with the military.

According to the Rev. Peter Geremia, an Italian-born American priest who worked with Favali, witnesses to the murder have been threatened and have left the village.

"The accused can go around more freely than the witnesses," he said. no legal action has been taken in a series of other killings attributed to paramilitary forces, Geremia said.

During her visit here, Aquino visited Favali's grave and referred to him in her speech as a victim of escalating violence under the Marcos government.

As in most of her other campaign stops, Aquino's appearances in Mindanao drew large crowds of enthusiastic supporters, who chanted her nickname at rallies and listened attentively as she talked of her experiences when her husband, opposition leader Benigno Aquino, was jailed under martial law and later assssinated in 1983.

However, a few of her better educated listeners acknowledged disappointment with her speeches, which they found shallow and too low-key.

"She should get away from emotional issues" and address the subjects of corruption, cronyism and the Marcos family's hidden wealth, one supporter said. "She should be on the offensive," he added, instead of constantly defending herself against Marcos' charges about links with Communists.

Still, he said, he intends to vote for Aquino because, "we would like to try something new. We are aware that what is lacking is morality, and we believe she has the moral qualifications."

As in Manila, some political observers here say it remains to be seen whether the enthusiasm for Aquino evident during her motorcades through the provinces will translate into votes on election day, especially if there is intimidation or widespread vote-buying by Marcos supporters.

There are indications that the Marcos political machine is no longer as powerful as it used to be. Residents of Davao, Mindanao's largest city, report that aside from putting up campaign posters along the highway north of town and paying local public school teachers, who work as inspectors at polling places, 150 pesos, or about $8.33, as a New Year's "gift," the ruling party's machinery has yet to be cranked up.