Which factor is responsible for the decrease in UUP seats?

The decrease in Ulster Unionist Party (UUP) seats can be largely attributed to the dominance of the Democratic Unionist Party (DUP) within Northern Ireland's political landscape. The DUP has positioned itself as the leading representative of unionist interests, particularly after the Good Friday Agreement. This shift in power dynamics has led to a significant consolidation of support for the DUP, often at the expense of the UUP.

Voters looking for a stronger unionist representation have increasingly turned to the DUP, especially during elections where the emphasis was on securing a robust unionist voice against other political groups. The effect of this dominance has been profound, resulting in the UUP losing key seats and influence over time. The sentiment among the electorate is often directed toward a desire for unity and strength, which the DUP has capitalized upon effectively.

Other factors such as strong responses to policy changes or the existence of effective outreach programs can have varying impacts, but they do not address the specific issue of inter-party competition and dominance, which is central to the UUP’s seat decrease. The UUP’s struggles in achieving comparable electoral success highlight the significant role that intra-unionist rivalry plays in Northern Ireland's current political climate.