The 'decline of political theory' refers to a period, particularly in the mid-20th century, when many scholars argued that political theory had lost its vitality and relevance. This perceived decline was largely attributed to several factors. The rise of logical positivism and behavioralism in political science emphasized empirical observation, quantification, and value-neutral analysis, leading to a skepticism towards normative and speculative political philosophy. Political theorists were seen as either engaging in mere historical exegesis of past thinkers or constructing abstract, untestable theories.

David Easton, for instance, argued that political theory had become either 'historicism' (studying past ideas without contemporary relevance) or 'moralism' (prescribing values without empirical grounding). The separation of facts from values, a core tenet of behavioralism, relegated normative questions to the realm of subjective preference, outside the scope of 'scientific' inquiry. However, this 'decline' proved to be temporary. The post-behavioral revolution, coupled with real-world political crises and social movements, led to a resurgence of normative political theory, demonstrating its enduring importance in addressing fundamental questions of justice, rights, and the good society.