Comparing Sinn Féin between North and South: Do institutional context and varying public attitudes drive party policy preferences?

One underexplored aspect of Sinn Féin is its position as an electorally competitive party that operates simultaneously in two separate jurisdictions. Sinn Féin’s operation (i.e. one centralised party, two jurisdictions) allows for a Most Similar Systems Design which can help determine how – and to what extent – its policy preferences differ between North and South. This also provides a test of issue competition and agenda-setting theory, which assumes that policy preferences must adapt to the unique vote and office-seeking incentives operating on political parties within states. This article draws upon new datasets from the Irish Policy Agendas Project and the Public Policy Agendas on a Shared Island project which have coded party manifestos (North and South) based on the Comparative Agendas Project coding scheme. The results support the assumptions made by issue competition and agenda-setting theory. Sinn Féin in the North tends to prioritise the representation of nationalist concerns, while Sinn Féin in the South focuses on more typical social democratic issues. But when nationalist interests are secure in Northern Ireland, Sinn Féin’s policy focus shifts to bread-and-butter issues that resemble its policy preferences in the Republic of Ireland.