Agapito Aquino is the only political novice among Philippine opposition politicians whose name is bandied about as a possible contender for the presidency.
Almost unheard of before his brother Benigno was murdered last August, the younger Aquino is now the leader of most mass actions against President Ferdinand Marcos. He is scheduled to visit the United States and Canada March 11 to 19 on a speaking and fund-raising tour sponsored by the Ninoy Aquino Movement , a political opposition group of expatriate Filipinos.
The best known of the Aquino-led protests was the Tarlac-to-tarmac ''marathon ,'' designed as a campaign to encourage voters to boycott last January's national plebiscite. The run from Tarlac, the Aquino family's hometown, to Manila International Airport where Benigno Aquino was shot, rekindled the subsiding rally fever in Manila when the runners were blocked by the military at the boundary of Manila.
''Butz'' (pronounced ''Butch''), as Agapito Aquino is fondly called, is spearheading opposition efforts to sustain antigovernment activities. At the end of February he launched another ''people's march,'' starting both from Tarlac in the north and from Batangas Province south of Manila. The aim of the march, which ended in Manila Tuesday, was to drum up support for boycott of the National Assembly (parliament) elections scheduled for May 14.
Aquino has not categorically denied that he has his eye on the 1987 presidential contest. Asked if he will join the fray, Aquino told the Monitor that at the moment all opposition efforts must be directed toward the restoration of democratic institutions in the Philippines.
''I have no plans (for the presidency) today, but if and when democracy is finally restored, I may consider it,'' he said.
Butz Aquino's detractors say he is riding the crest of popularity of his slain older brother, who was Mr. Marcos's archrival. If Marcos had not declared martial law in 1972, Benigno Aquino would likely have been elected president at the national elections originally scheduled for 1973. And when Benigno Aquino announced his return to Manila last August after three years of self-exile in the US, it was widely expected that he would be the successor to Marcos.
An oft-quoted statement from the younger Aquino shows that he does recognize that his brother's name and reputation have indeed helped raise him aloft. He has said that there are three main reasons why Filipinos will support him: ''First, I look like Ninoy (Benigno's nickname). Second, I sound like Ninoy. And third, I don't have a first lady.''
He was referring to Imelda Marcos, the President's powerful wife, who is widely criticized for her luxurious, prestige projects. Aquino, father of three, is separated from his wife.
Nevertheless, Aquino said he could not quite measure up to his brother's political sophistication.
''His shoes are too big for me to fill,'' he said.
He also admitted that his brother had an extremely sharp mind, able to grasp an idea in half the time that he himself would take.
Before his brother's death, Butz Aquino was a full-time businessman heading a profitable fiberglass manufacturing firm. He occasionally dabbled in acting. Young businessmen and business executives have actively supported his rallies and marathons.
As a businessman, Aquino's policy ideas are clearest in the economic area. He says he favors a social market economy akin to those in Scandinavian countries.
''I've always been impressed by the Scandinavian systems which are capitalistic in nature but are deeply concerned with social responsibility,'' Aquino told the Monitor.
Aquino also seems careful not to antagonize the US, particularly with regard to its bases in the Philippines, the two largest US bases in Asia. Appearing to distance himself from the strident nationalists in the opposition who demand no less than a dismantling of the bases, Aquino said the government must negotiate a gradual phase-out that would give the US time to find other sites.
But wider still is the distance between Aquino and the opposition parties participating in the May assembly elections. The United Nationalist and Democratic Organization (UNIDO) and the Pilipino-Democratic Party-Laban (PDP-Laban), his late brother's political party, have announced plans to participate in the elections. This is despite an earlier agreement among all opposition groups and parties to boycott if Marcos did not heed their demands for safeguards to ensure an honest election.
Meanwhile, a UNIDO member said that Aquino's boycott movement has been penetrated by leftists who could use it to sow sporadic violence during the election. But Aquino countered that his group has provided safeguards so it will not be run over by the leftists.
''A majority of the group are for non-violence, and we are therefore maintaining a tight organization among this majority,'' Aquino said. ''Everything we do falls under the non-violent ideals of Ninoy,'' he added.
A PDP-Laban official told this newspaper that Aquino could yet be expected to ''fall in line'' with the election participation move since Corazon Aquino, Benigno's widow, whose opinions and decisions hold great sway in the opposition camp, endorsed participation in a carefully worded statement last week.
Many old-timers in opposition politics are not impressed with Aquino's bid for national leadership.
''Running a country is not quite like running in a marathon,'' jested one.
Another oppositionist suggested that Aquino's activities are tolerated by Marcos and the military since Aquino is an inexperienced politician whom they think they can handle easily.