Great-Power Competition, Conflict and Power Balance within Strategic Territories

Existing research typically assumes that external support from great powers strengthens incumbent local elites. We challenge this view by showing that the effect can run in either direction, depending on whether intervention raises or lowers a great power's probability of keeping the territory. We examine the neighbouring islands of Corsica and Sardinia during the conflict between Aragon and Genoa (1351–1444). As rivalry intensified, both islands became more valuable. On Sardinia the incumbent reinforced the feudal order and elite rents rose. On Corsica it withheld support; the lords then lost ground they had held when they were backed alone, and rural communities gained power. A four-player game with two great powers, a local elite and local society accounts for the divergence. The rent the elite can extract is pinned down by how likely a revolt would have been to succeed had it taken place, which depends on who would have intervened. An extension with incomplete information about how much each island was worth explains why a mutually costly war persisted before a negotiated settlement.