The War of the Triple Alliance, fought from 1864 to 1870 between Paraguay and the Triple Alliance of Brazil, Argentina and Uruguay, was a Latin American regional war that spiraled out of control to become one of the bloodiest international confrontations in the Western Hemisphere. Expanding beyond the ability of the combatants to manage it, the war nearly devastated all the actors, particularly Paraguay, whose people suffered inconceivable casualties and privations. This thesis examines the War of the Triple Alliance as a historical case study to determine the complex causes and catalysts behind this nineteenth century regional conflict. The case study presents the casus belli of each of the primary actors, and infers that balance of power perceptions may have exacerbated the root causes of war. The thesis argues that this little-known and misunderstood war holds unexploited lessons toward modern-day applications in comprehending regional conflict.