ABSTRACT
Anticipating some recent scholarship (Buzan & Lawson, 2013; Knutsen, 2008), we begin our
analysis of major twentieth century debates by looking back into their origins in the late nine-
teenth century. Over the course of the long twentieth century (from 1870 to roughly 2020),
three major doctrinal debates in three different periods have dominated the inter-related theories
and practices of global security. The first was the debate between theories and practices of com-
petitive European power balancing and the emergent alternative of collective security, first insti-
tutionalized at the end of WWI in the League of Nations. The second was the debate between the
architects, analysts, and practitioners of bipolar competition that emerged out of during the Cold
War and their challengers from the periphery, who bore the costs of the stability of the order
between the two superpowers. The third was between analysts of unipolarity at the end of the
Cold War and its antinomies from state resistances to humanitarian intervention and from trans-
national threats like terrorism. These ‘great’ debates were/are conducted by and can be found
within the scholarship of major intellectual figures of the century. They involved sustained
and focused discussions between advocates and critics of different positions, among individuals
arguing their positions, responding to each other (directly or indirectly), making qualifications,
occasional concessions, refinements, and proposing synthetic, new reformulations. Although the
term ‘global’ is usually associated with security discussions of the last quarter century, we
describe these twentieth-century debates about security as ‘global’ because, as will be shown
below, they simultaneously engaged individuals and movements found in all, or at least most,
parts of the world.
