In 1866, while Brazil, Argentina and Uruguay were involved in the War of the Triple Alliance against Paraguay, Mariano Melgarejo, the dictator of Bolivia, threatened to send a military force to help Solano Lopez. The Brazilian government reacted quickly, and sent a diplomatic mission to La Paz. After some negotiations, which included to give two white horses and four medals of honour to Melgarejo, the Brazilian mission ensured the Bolivian neutrality in the conflict. Also, they made Melgarejo sign a treaty which recognized the Brazilian possession of a huge litigious are on the border of both countries.
However, WI Melgarejo had been more stubborn and had declared war against the Triple Alliance, creating two more fronts, in Northern Argentina and in Mato Grosso? How would this affect the war?