In: International Relations.<\/p>\n
While South America made significant strides in regional security cooperation since the 1990s, more recently the region seems to have entered a process of backsliding from its cooperative achievements and towards mere coexistence. This article proposes that an English School approach allows for a nuanced assessment of regional security cooperation. It contributes to the analysis of regional international societies and regional organisations as markers of fundamental institutional change. While scholars have studied how regional organisations shape the fundamental institutions of regional international societies as they emerge and evolve, little research has been done on whether a decline in regional organisations can lead to changes in the fundamental institutions of regional international societies. Using a set of indicators for coexistence and cooperative international societies, we analyse whether there is evidence of backsliding from cooperation to coexistence in South America with regard to three different types of security challenges: interstate conflict and militarisation; inter-mestic repercussions of internal conflict and violence; and extra-regional influences. We argue that a decline in regional organisations exacerbates those challenges, as they are no longer mitigated through institutionalised diplomatic procedures. However, despite the organisational decline, fundamental institutions in South America have so far proven relatively resilient.<\/p>\n