New York — Like many Philippine political leaders before him, Agapito Aquino, younger brother of the slain opposition leader Benigno Aquino, has bolstered his credibility with a politically motivated trip to the United States.
The younger Aquino has attracted attention both in the Philippines and in the international press because of his active role in organizing anti-government protests in the Philippines.
But he has had to answer questions about his political inexperience. Before his brother Benigno was assassinated last Aug. 21, Agapito (Butz) Aquino's contact with the public was achieved through his dual career as entertainer and businessman.
Interviewed last week in New York, he professed a ''disdain for politics and most politicians,'' a statement he has made often during the seven months since his brother's death.
But in meetings in Washington last week with State Department officials and several key members of Congress, he presumably kept those feelings to himself.
In Manila over the weekend, President Ferdinand Marcos charged that opposition leaders who have visited the US in recent weeks - including Aquino and former Senator Salvador Laurel - were seeking US support for the legislative elections in May. He denounced any American involvement in Philippine domestic politics.
(''It is not the business of Americans to decide who is going to be the president of the Philippines,'' President Marcos declared Sunday, according to UPI.)
Aquino said he received ''moral support'' from Deputy Assistant Secretary of State John Monjo, but no indication that the State Department would formally encourage or provide financial assistance to the Philippine opposition movement.
''I had the impression that they want to do more but can't,'' he said. ''It seems as though their hands are tied. Maybe we haven't offered a clear alternative to Marcos maybe they are not convinced we can succeed.''
Aquino received a more enthusiastic reception from Sen. Edward Kennedy of Massachusetts and Rep. Stephen Solarz, a New York Democrat who heads the House Subcommittee on Asian and Pacific Affairs. Aquino said he welcomed Solarz's proposal to divert a portion of US aid to the Philippines from military to social and economic programs.
''What I really wanted was total suspension of US aid, but that is not realistic,'' he said. Congress is considering a $900 million aid package as payment for US military bases in the Philippines.
In the interview, Aquino expressed critical views about US policy in his country similar to those held by staunch Filipino nationalists. However, some of his positions place him in the company of opposition figures who are on good terms with the US government.
Sounding very much like nationalist former Senators Lorenzo Tanada and Jose Diokno, Aquino said US foreign policy in the Philippines was based on a ''double standard.''
''The Americans espouse democracy, practice it in their country, and seem to be very proud of being the leaders of the free world,'' he said, ''and yet in the Philippines they are supporting a dictatorship. Outside their country, Americans seem to value economic and strategic interests over and above the value and principles of democracy.''
But like former Senator Laurel, who has strong ties to the US, Aquino does not favor immediate removal of US military bases at Subic Bay and Clark Air Field.
''We should have a referendum on the issue of the bases when the current lease expires in 1991, but as far as I'm concerned, it's not even an issue at this point,'' he said.
Aquino stands with the nationalists in calling for a boycott of the elections scheduled for May 14. This has led to some friction between himself and Laurel.
As head of the United Nationalist Democratic Organization (UNIDO), one of the largest opposition groups, Laurel is planning to field an extensive slate of candidates to run against those of Marcos's ruling party, the Kilusang Bagong Lipunan (New Society Movement).
During his nine-day speaking tour of the US and Canada, Aquino explained to his audiences why he and several other opposition leaders have been urging their countrymen to boycott the elections.
''What we want is a legislature that is independent of the executive branch. This would move us back towards democracy; but Mr. Marcos retains his power to legislate without consent. Therefore the parliament is meaningless - it's not worth fighting for,'' he said.
The question of participation in the May elections also may have put some distance between Aquino and his brother's widow, Corazon Aquino, who, in a recent speech urged Filipinos to vote as a means of nonviolent participation in the political process.
''The whole family got together in February to discuss the elections,'' Aquino said, ''and we unanimously agreed to call for participation only if Marcos agreed to revoke his legislative powers and rescind the decrees he has issued since martial law was declared in 1972.
''Since he has not complied, I think we have to boycott the election. It seems as if Cory (Corazon Aquino) has changed her mind, but I still respect her opinions. But I'm not going to change my opinion. I think our country needs credible leaders who will not make wishy-washy decisions.''
Aquino denied that he is harboring political aspirations, although he has been mentioned as a possible presidential candidate. President Marcos's current term expires in 1987. If Aquino were to run for elective office, he would undoubtedly have to answer more questions about his dramatic rise to national prominence.
''Before August, I was not prepared to lay my life on the line,'' he conceded. ''But when my brother set the example, I decided I would do the same. Some say I'm basking in my brother's glory, and are questioning my sincerity. Well, what do they expect me to do? Do I have to get shot to prove my sincerity?''
Aquino said he had already attained widespread credibility in the Philippines , noting. ''I seem to have created a following during the last six months.''