The first regional institutions in the Americas emerged in the 1820s as the successor states of Spain's American empire sought to construct stable, amicable, and productive relations between themselves. A relatively thick array of international institutional rules had emerged by the 1930s, well in advance of the foundation of the first formal international regional organizations in the hemisphere and three decades before the establishment of the first successful international subregional institutions. In the international relations of the Americas, the analysis of the emergence of institutional rules must to some extent be decoupled, therefore, from the analysis of organizations.

Yet not until the 1990s did international regional and subregional institutions in the Americas effectively promote trade, defend democracy, coordinate foreign policies, and contribute to an international milieu that reduced the frequency and intensity of militarized interstate disputes over territory and settled many of those disputes. International regional institutions in the Americas did not, therefore, have a crafting moment or a master architect. They resulted from the long accumulation of failures and occasional successes. The analytical task requires explaining the early establishment, long survival, delayed effectiveness, and eventual implementation of the rules of this array of international regional institutions – long periods of stasis followed by change.

In this essay, I argue, first, that the idea of international regionalism was a response to security problems in the immediate aftermath of Spanish American independence in the 1820s. This ideational legacy lingered well beyond the founding cause, however.