The politics of regional integration: Domestic support for the enlargement of Mercosur in South America

While there has been scholarly attention to the politics of the third wave of regionalism in South America, this typically focuses on the performance of the Executive Branch rather than the domestic constraints. This article innovatively compares the behaviour of Mercosurian parliaments to understand their role in regional integration. It contributes to Foreign Policy Analysis, by drawing on Qualitative Comparative Analysis to systematically identify the configurations of conditions for rapid approval of enlargement treaties and investigate the impact of national parliaments. Nine cases are analysed related to the episodes of enlargement of Mercosur to empirically test the political conditions to achieve fast approval of treaties. The key finding is that domestic support (channelled in national parliaments) is important to confirm and conduct international projects – and specifically regional integration. This has implications for understanding the possibilities for how future accessions to Mercosur and other regional organisations will take place.