The nature of the political party in Taiwan has been insufficiently problematized in recent writings on the island's elections. Based on field research this article argues that the informal structure of political support in Taiwan takes the shape of nested pyramid structures, built of successive dyadic support relations between politician and supporter and two politicians at different hierarchical levels, culminating in a handful of top political leaders. The political party is only the widest kind of support network, and in lower-level elections not the central agent. The dyads in Taiwan politics differ from traditional patron–client relations in being more dynamic, equal and voluntary. This informal political structure coupled with generally weak party loyalty and large benefits of incumbency produces pervasive party instability and subsequent election instability at higher election levels. The number of top political leaders and relations between them are critical in structuring the party scene.