Why does institutional instability pervade the developing world? Examining contemporary Latin America, Institutions on the Edge develops and tests a novel argument to explain why institutional crises emerge, spread, and repeat in some countries, but not in others. The book draws on formal bargaining theories developed in the conflict literature to offer the first unified micro-level account of inter-branch crises. In so doing, Helmke shows that concentrating power in the executive branch not only fuels presidential crises under divided government, but also triggers broader constitutional crises that cascade on to the legislature and the judiciary. Along the way, Helmke highlights the importance of public opinion and mass protests, and elucidates the conditions under which divided government matters for institutional instability.