The main significance of the Spanish-American War, fought in 1898, was the emergence of the United States as a global power and a shift in its foreign policy. Driven by imperialistic ambitions and a desire to liberate Cuba from Spanish rule, the U.S. engaged in a brief but decisive conflict that resulted in a swift victory. Following the war, the Treaty of Paris was signed, granting the U.S. control over territories, including Puerto Rico, Guam, and the Philippines. This expansion marked the beginning of American imperialism and the country’s active involvement in international affairs, setting the stage for its later role as a world leader in the 20th century.