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

One underexplored aspect of Sinn F & eacute;in is its position as an electorally competitive party that operates simultaneously in two separate jurisdictions. Sinn F & eacute;in'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 F & eacute;in in the North tends to prioritise the representation of nationalist concerns, while Sinn F & eacute;in in the South focuses on more typical social democratic issues. But when nationalist interests are secure in Northern Ireland, Sinn F & eacute;in's policy focus shifts to bread-and-butter issues that resemble its policy preferences in the Republic of Ireland.