The signing of the joint resolution by President William McKinley marked a significant escalation in U.S. involvement in Cuban affairs, triggered primarily by Spain's oppressive rule over the island. Cuban revolutionaries had been fighting for their independence from Spanish colonial control, which attracted increasing sympathy from the American public and politicians alike. Public sentiment turned sharply following the explosion of the USS Maine on February 15, 1898, in Havana Harbor, which was popularly attributed to Spanish sabotage, despite later analyses indicating it was likely an accident. As reports of atrocities by Spanish troops against Cuban civilians flooded American newspapers through yellow journalism, calls for intervention grew louder.

In response to these conditions, McKinley submitted a draft of the resolution for war to Congress. It included stipulations ensuring Cuban independence while also providing for U.S. military intervention to force Spain to withdraw. Congress overwhelmingly supported this resolution on April 19, 1898. The next day, McKinley formally declared war, setting in motion a conflict that would last just over three months. The Spanish-American War would eventually lead to significant changes in U.S. foreign policy, marking the nation’s emergence as a global power.

Following the declaration, U.S. forces quickly mobilized and won decisive battles both in the Caribbean and the Philippines, effectively dismantling Spanish colonial rule there. The Treaty of Paris, signed in December 1898, would formalize the transfer of sovereignty over Puerto Rico, Guam, and the Philippines from Spain to the United States, fundamentally altering the global landscape.