The aim of this article is to examine the role of Catholic political thought in relation to the history of European integration and show how the shift away from this communitarian tradition by mainstream social democratic and conservative parties can help explain the rise of populism. The idea of Europe as a unified entity has always been grounded in its Christian character, and this was the basis of the Christian Democratic pan-European project of the EU’s ‘founding fathers’ in the mid-twentieth century. The rise of both social and economic liberalism in the ensuing years led to a disconnect between the political establishment – who remain largely supportive of the project – and growing numbers of disaffected citizens. A refocusing of the political narrative in relation to European integration on the continent’s communitarian and Christian (and Social) Democratic traditions could halt the advance of populist-nationalism and Eurosceptic parties.