This book answers the question of why and how people form bonds with each other and with insurgent groups in fragile state contexts. It develops an overarching framework depicting a political social contract, presents the Grievance-Driven Pathway as one way through which a reformist insurgency-society contract can form, and conducts a systematic comparison using two novel case studies not yet evaluated in insurgency literature, the UFDR in the Central African Republic and the SLM/A in Darfur, Sudan. The core claim is that perceptions of legitimacy across the four social contract elements lead to consent to form the intangible “bond� and foster societal and political trust. Studying social contracts—specifically the interaction between state-society contracts and reformist insurgency-society contracts—facilitates a greater understanding of what constitutes legitimacy in the twenty-first century and how perceptions of illegitimacy can lead to a breakdown of trust and the outbreak of violent conflict.