Why is it that in many protracted ethnonational conflicts, the strategies adopted by national self-determination movements and the governments of states that rule over them appear as “irrational” and suboptimal? What explains inefficiency in the strategic adaptations of self-determination movements and host state governments? This dissertation addresses these questions in the context of the Israeli-Palestinian conflict. It analyzes patterns of strategy formation and strategic adaptation in the interactions between the Palestinian national movement and Israeli governments across a series of contentious episodes, beginning with the Oslo Accords. It reconstructs the shifting strategy sets of a core set of actors through the rise and fall of the peace process, then traces emergent trends of mobilization its aftermath. The analysis of different processes of strategy formation suggests that strict rationalist models of conflict behavior have significant shortcomings that often lead to faulty explanations and predictions. Many types of common strategies are formed less through rational, guided processes of design than through evolutionary processes of bottom-up emergence. This reality has implications for how social scientists model ethnonational conflict and explain suboptimal outcomes. The Israeli-Palestinian conflict demonstrates these problems and the dissertation provides the outlines of an alternative model.