South America war is unlikely.
Fedirka 16 Allison Fedirka, senior analyst for Geopolitical Futures, previously worked at Stratfor the Latin America regional director, international relations master's degree from the Univeristy of Belgrano. [How South America Has Avoided Interstate War, 2-15-2016, https://geopoliticalfutures.com/how-south-america-has-avoided-interstate-war/]
The 80-year absence of interstate warfare in South America is noteworthy. From the standpoint of modern geopolitics, this is a truly a rare event. Geography discourages most of these countries from forming strong interdependent relationships and also makes it difficult to use key elements of modern warfare. Significant technological advancements in infrastructure, transportation and military hardware would be necessary to overcome these geographic challenges. Given our current model of the Western Hemisphere, this absence of interstate warfare in the region can be expected to continue for the foreseeable future. As a result, domestic issues – drug trafficking, guerrilla groups, disease, natural disasters, etc. – will remain by far the largest security threats to South American nations.