The War of the Triple Alliance occurred because of Paraguayan foolishness. By this, I mean after Paraguay and Brazil were at war, the Paraguayan President, Solano Lopez, wanted to move troops through Argentina. When Argentina refused, he declared war. So what if he didn't do this enormously foolish move, and the war remains between Paraguay and Brazil? This will drastically increase Paraguay's chances of winning the war, which is a likely scenario if it remains between the two of them. While Brazil is far larger, Paraguay had a larger and more professional fighting force, and tried to be "The Prussia of South America", whereas Brazil had a poor, unorganized army. What would the effects of this war be?