Three months before the mock battle, Dewey's Asiatic Squadron had destroyed the Spanish fleet in Manila Bay on May 1, 1898. By June, Filipino revolutionaries under General Antonio Luna had dug fourteen miles of trenches around Manila and seized the city's only pumping station, cutting off its water supply. Inside the walled district of Intramuros, the population had swollen from ten thousand to roughly seventy thousand, and conditions were desperate. Some 12,000 American troops had landed by late July under Major General Wesley Merritt. The Spanish knew they were beaten, but Governor-General Jaudenes faced an impossible choice. Surrendering to the Americans was humiliating. Surrendering to Filipino revolutionaries under Emilio Aguinaldo was, from the Spanish perspective, unthinkable. Jaudenes proposed a solution through the Belgian consul, Edouard Andre: stage a short battle, raise a white flag, and hand the city to the Americans, who would keep the Filipinos out.

The plan called for a token bombardment followed by an American advance, after which the Spanish would surrender. Dewey directed his ship captains to spare Manila any serious damage, but gunners on one vessel, unaware of the arrangement, scored several direct hits before their captain could cease firing. On the ground, General Francis V. Greene's brigade pushed through Malate and over the bridges to occupy Binondo and San Miguel. General Arthur MacArthur Jr. advanced along the Pasay road, overcoming blockhouse resistance before securing Malate. Shortly after, a white flag appeared on the walls of Intramuros. The choreography had worked, mostly. What nobody had planned for was that the Filipino revolutionaries, seeing what looked like a genuine assault, joined the attack. Although the Spanish were waving flags of truce, Filipino forces opened fire, provoking return fire. Six Americans and forty-nine Spaniards died in what was supposed to be bloodless. The 'mock' had turned real.

At 8:00 that morning, Aguinaldo received a telegram from General Thomas Anderson sternly warning him not to let his troops enter Manila without American consent. Aguinaldo ignored it. His forces had besieged the city for months, had cut its water, had bled for Philippine independence. Now they were being told the liberation they fought for was not theirs to claim. The Americans and Spanish had agreed on one thing: Filipino forces would not be allowed inside Intramuros. After the surrender, Aguinaldo demanded joint occupation of Manila. The request was denied. American commanders pressured him to withdraw his forces, and weeks of tense negotiations followed. By September, Aguinaldo ordered his troops to pull back from their most advanced positions. The Filipinos felt profoundly betrayed. They had looked to the Americans as liberators aiding their fight against Spanish colonial rule, only to discover they were being replaced by a new colonial power.

Neither Dewey nor Merritt knew, as the white flag rose over Intramuros on August 13, that a peace protocol between Spain and the United States had been signed the previous day. They learned of it three days later. For the Philippines, the end of one war was the beginning of another. Tensions between American and Filipino forces escalated through the fall and winter. On February 4, 1899, an American private fired on a Filipino revolutionary soldier near the San Juan Bridge. Filipino forces returned fire. When Aguinaldo sent a messenger to General Elwell Otis explaining that the shooting had been against his orders, Otis replied with words that closed the door on any reconciliation: 'The fighting, having begun, must go on to the grim end.' The Philippine-American War that followed would last years, claim hundreds of thousands of Filipino lives, and leave scars that shaped the relationship between the two nations for over a century.