In accordance with the terms of the Pact of Biak-na-Bato, in which had terminated the  abortive revolt of the Filipinos against Spanish authority in 1896, Aguinaldo and forty other Filipino leaders were living in voluntary exile in Hong Kong at the time war between the United States and Spain was declared in 1898. But while Admiral Dewey and his squadron were crossing the Pacific in route to Manila Gen. Aguinaldo left Hong Kong for Europe via Singapore. Apparently the idea of arranging for cooperation between Gen. Aguinaldo and Admiral Dewey originated with the  American consul at Singapore.  On April 27, 1898, shortly after his arrival at Hong Kong, Admiral Dewey received from the American Consul at Singapore a cablegram stating that Gen. Aguinaldo was then at Singapore and willing to return to Hong Kong and accompany Admiral Dewey to the Philippines in order to arrange for cooperation between the American forces and the Filipinos, who, it is learned from other sources, were already again in open rebellion against Spanish rule. Admiral Dewey cabled a reply advising Gen. Aguinaldo to return to Hong Kong, but left Hong Kong for Manila before Aguinaldo’s arrival. It also appears that, probably through the intervention of the American consul at Hong Kong, two of the Filipino leaders who were then   living in Hong Kong were permitted to accompany Admiral Dewey to the Philippines, where, on May 1, 1898, they witnessed the Battle of Manila Bay in which the Spanish fleet was destroyed.  Following the said battle Admiral Dewey sent the U.S. dispatch boat, the McCullosch, to Hong Kong to pick Aguinaldo, who arrived at Cavite on May 19, 1898. [35]

Gen. Aguinaldo immediately set about organizing Filipino Revolutionary Government. The American force in the Islands at that time was too small to oppose this move, even though its leaders had wished to do so, and it is probable that the leaders of the America force expected that Gen. Aguinaldo would cooperate with them in the impending campaign against the Spanish force at Manila.  Major F. L. Palmer wrote an American army officer who served in the Philippines during the early years of American occupation the following discerning account.

Without going into details, we may note that from the very beginning of their cooperation in 1898, the Americans and Filipinos were at cross - purposes with each other.  The American policy at that time was too vague and uncertain to be convincing to anyone, especially to Filipinos, who, misled by their own ardent desires, too readily invested the Americans with the status of allies in their own struggle for liberty.  Hence, the Dictatorial Government set up by Aguinaldo at Cavite on May 24 was probably regarded by the Americans as merely a means of controlling the Filipinos and holding them in check, while the latter looked upon it as a preliminary step to a government of the Philippines by and for the Filipinos themselves. 

On June 16, Aguinaldo claimed that he was called upon to assume the role of Dictator, and five days later, the Revolutionary Government was declared with the avowed object of struggling for the independence of the Philippines until all nations, including the Spanish, shall expressly recognize it, and to prepare the country so that a the Republic shall be established.  This all took place with the knowledge of the Americans, but they were powerless to enforce any objection or protest as the only forces available were those at the ships and at Cavite, So the breach  continued to widen, and the Filipinos passed from American control.

Meanwhile, troops had been organized in the United States to go to the Philippines and assure the results of Dewey’s victory.  They arrived on July 16 and were see landing south of Manila, which they invested on that side well as on the Bay, while the Filipino forces encircled it on all other sides. Friction between the forces increased continually, until, on August 1, the  Declaration of Independence of the Filipino nation was issued.  This foreshadowed a crisis,  evident alike to American and Spanish, and necessitated prompt and concerted measures to protect Manila and the lives and property of its inhabitants from the revengeful excesses of Filipinos should they succeed in entering the city.  Negotiations were accordingly entered into between the Americans and the Spaniards, as a result of which Manila surrendered on August 13, after a short bombardment, and the Americans assumed control without allowing the  Filipino to enter the city.  And when the Stars and Stripes replaced the Spanish flag over old Fort Santiago, the Spanish dominion over the Philippines passed away forever, and that of the United States came into existence.

American outposts were established around Manila, facing those of the Filipinos, who had become, in fact even if not as yet in act, insurgents against the American Government.  Both forces were uniformed, armed, equipped, and under military control, and all of the courtesies and  outward semblance of friendship were scrupulously observed, the leaders on both sides desiring to avoid a breach and hoping for an amicable settlement of all difficulties through diplomatic means. 

Early in September Aguinaldo moved his headquarters to Malolos, on the railway and about 20 miles north of Manila; these on September 15, the first Filipino Congress assembled, and the Revolutionary Government was perfected and put into effective operation practically  throughout the Islands except in places actually held by either Americans or Spaniards. Continually, the strain grew more tense, and at last, on the night of February 4 - 5th, the clash came and the long expected war of the Insurrection began, Malolos continued the seat of the Revolutionary Government until it was captured by the Americans on March 31, 1899, when Tarlac became the new capital, to be followed later by Bautista; each of these towns was also upon the Manila - Dagupan railway, and successively farther north.  Military operations went on, but the Insurrection was practically at an end when Dagupan was captured and the whole line of railway came into the possession of the Americans, in November 1899. [36]