Theoretical Foundations of Constitutional Democracy in Nigeria: A Critical Realist Examination of the 1999 Constitution’s Legitimacy Deficit

The 1999 Constitution of Nigeria was promulgated by a military decree without the participatory constitutional convention or popular ratification process that legitimacy theorists argue is foundational to constitutional democracy. This legitimacy deficit has been persistently invoked in academic and political discourse as an explanation for the Constitution's governance failures, yet a theoretically rigorous examination of its implications using Critical Realism as an analytical lens is absent from the Nigerian constitutional law literature. This study applies a Critical Realist theoretical framework to examine the legitimacy deficit of the 1999 Constitution, developing an original model of constitutional legitimacy that integrates procedural, substantive, and sociological dimensions specific to the Nigerian context. The study applies Retroductive reasoning to identify the causal mechanisms through which constitutional illegitimacy produces governance failures, examining the Constitution's democratic origins, its substantive rights design, public perceptions of constitutional authority, and the frequency of constitutional bypass practices by elected officials. A multi-source methodology combines doctrinal analysis of the Constitution with empirical analysis of Afrobarometer public legitimacy surveys from Nigeria for 2020 and 2022, and comparative constitutional legitimacy analysis from post-apartheid South Africa. The study's original theoretical contribution is a Contextualised Constitutional Legitimacy Framework applicable to African post-military constitutions. Findings generate a theoretically grounded constitutional reform agenda directed at a participatory constitutional conference. Keywords: constitutional legitimacy, Critical Realism, 1999 Constitution, democratic governance, Nigeria.