In my research project I investigate the paradox of European imperial longevity in the Americas when compared to the second European empires in Africa and Asia (19th-20th centuries). The aim is to offer a new argumentative narrative for understanding imperial cohesion and centrifugal forces that ultimately led to colonial secession. This narrative is based on zero-sum thinking which I interpret as a main driver. Herein, I identify several fragile phases which I use as a foundation for historical theory formation, while focusing on the US-American Revolution of 1776. I investigate how zero-sum thinking became a problem for imperial stability because colonists were no longer afraid of their potentially hostile neighbors (due to inter-imperial consolidation after the Treaty of Madrid of 1750 and France’s loss of the French and Indian War in 1763); because the thought of zero-sum expansion could still be pursued at the cost of the indigenous (“frontiers”); because zero-sum thinking was no longer a defining idea of economic growth and prosperity (mercantilism loses support); and because the spread of universalism of ‘sovereignty’ entered the socio-political stage and forced reforms that were not met (in the case of the British) or partially and insufficiently met (in the case of the Spanish, i.a. Cádiz Cortes). Following the argument of imperial fragility throughout the centuries, the US-American Revolution has to be seen in a historical line of fragility which was then ultimately cut.