Manila — ''Americans and Filipinos, we are brothers,'' enthuses the young Filipino, squinting into a searing Manila sun. ''Eight members of my family live in California.''
President Reagan's warm reception for President Ferdinand E. Marcos during his visit to the United States has highlighted the special relationship that began when the US conquered the Philippines and made it a colony at the turn of the century.
The Reagan administration has broken from the Carter administration to strike a more cooperative chord with Marcos. From the Reagan viewpoint, the strategic importance of US bases in the Philippines supersedes the need for any finger-wagging, at least in public, about the strong-man rule of President Marcos.
During the Marcos visit, an administration source was quoted as saying that the human-rights issue did not even come up in personal contacts between the two presidents. One sign of warmer relations was the statement by an administration official that human-rights abuses have decreased since martial law was ended in the Philippines about a year ago.
Another sign was the ceremonial presentation of US war medals to President Marcos for his role in fighting the Japanese in World War II. Defense Secretary Caspar W. Weinberger hailed the Philippine leader as ''an old friend and a compatriot in arms'' while awarding him the Distinguished Service Cross, Silver Star, and Purple Heart.
The depth of the sensitivity about Washington-Manila ties was vividly on display both before and during Mr. Marcos's Washington visit. The Philippine leader had sent a platoon of advance men and public relations people ahead to counter any negative publicity that might be stirred up by Filipino opposition leaders in the US. Opposition leaders begun planning demonstrations well before Mr. Marcos's arrival.
Reagan administration officials tend to play down the suggestion of any major improvement in relations since the Carter days. But one says, ''It goes along with the President's desire to improve ties with our allies,'' adding that the Philippines is ''one of our earliest allies.''
In the Philippines there is little doubt of a changed mood in Washington. In a recent interview, Marcos himself said, ''There has been a change in the sense that the Reagan administration has tended to clarify policy pertaining to Asia and to the world.''
In its drive to counter growing Soviet influence around the world, the Reagan administration has sometimes raised strong criticism for throwing support to authoritarian regimes. Washington's apparent shift toward Marcos has become an emotional issue, both inside and outside the Philippines.
The chummier ties also highlight Washington's continuing policy dilemma: Is the best way to ensure long-term relations with the Philippines to snuggle up to the authoritarian Marcos regime, perhaps alienating some future leadership, or should the US maintain a degree of detachment?
And beyond the chants of demonstators and the friendly speeches by the two presidents, there are issues ahead that will test the friendly ties between the two countries:
* Military bases agreement. Although the agreement on Subic Bay Naval Base and Clark Air Base is not up for review until 1984, the US may want assurances that no glitches will arise in negotiations. The Philippines wants greater control over these US installations, the largest American military installations outside the continental US.
''There must be more concrete indications of Philippine sovereignty over the bases,'' says a Philippine Foreign Ministry official. Manila also wants more military hardware.
* Economic aid. Manila would like greater access to US markets for products such as sugar, textiles, and garments. The US pays Manila about $100 million a year in military and economic support. US and Filipino workers and personnel at the bases generate another $150 to $200 million for the local economy. Trade between the two countries topped $3.5 billion last year.
* Political stability. The US is interested in seeing continued political stability in the Philippines. For Washington this may mean urging a smoothing of relations between Marcos and the fragmented moderate opposition in the Philippines.
Opposition leaders, arguing that the radical left is rapidly gaining strength , have been urging Mr. Marcos to step down. ''Unless something drastic is done, we may be confronted with either a military takeover or chaos,'' says Salvador Laurel, president of a moderate opposition coalition.
The US will also be trying to get a clearer bead on who will succeed Marcos. Rumors of the leader's ill health persist. In addition there have been signs of growing political uncertainty recently. Nevertheless, he is likely to remain in power for the next few years, provided there is no deterioration in his health, diplomats say. When he appointed her to a committee that is to be his temporary successor, Mr. Marcos fueled speculation that his wife would succeed him.
''The state visit is a crucial time for the US to get a feeling about succession,'' says Dr. Belinda Aquino, director of the Philippine studies program at the University of Hawaii. ''The longer he rules without a clear signal on succession, the greater the insecurity in the country.''
The resumption of ''special relations'' between Manila and Washington is also seen in the flurry of high-level US officials sent to the Philippines in the past two years, including former Secretary of State Alexander M. Haig Jr., Defense Secretary Weinberger, and Vice-President George Bush.
More than three decades of independence have often strained but not severed relations between the Philippines and the United States. Although some of the great European powers have witnessed hostile partings with many of their far-flung domains, US-Philippine ties have endured in political, cultural, and economic areas.
Four successive US administrations, from Nixon through Carter, have cooperated with the Marcos regime, understanding the importance of the two key military bases in the Philippines.
At the same time, however, the US was careful to avoid endorsing martial law, imposed by Mr. Marcos in 1972 but lifted in January of last year, in a country touted in the past as America's ''window of democracy'' on Asia. The Carter administration, by trumpeting the cause for human rights, went one step further in distancing itself from the Marcos regime.
Besides the strategic importance of the Philippines, the countries share historical and economic links. Still, residues of mistrust and discontent remain over US military presence here and the control wielded by multinationals and US-dominated financial institutions in Filipino economic affairs.
But for many Filipinos the United States remains the land of milk and honey. The US is seen as a benevolent cousin many would like to call on for an indefinite stay. This is evidence at early dawn each day when Filipinos, toting tales of hardship and unemployment, line up in front of the US Embassy on palm-fringed Roxas Boulevard hoping for visas to travel to the US.
Filipinos crave things American, from thigh-hugging designer jeans and thriller movies to Shakey's pizza. Filipino firms also study Western business methods.