Towards a theory of militant constitutionalism

Manenschijn, J.I. (2026)

Doctoral Thesis

Constitutional democracies worldwide are experiencing backsliding, with only 45% of the world’s population living in a democracy. Paradoxically, one of the most urgent threats to constitutional democracy seems to come from within: democratically elected leaders are using the structures of constitutional democracy to dismantle the system from within. This dissertation explores the issue of constitutional backsliding through a case study of the United Kingdom, highlighting how difficult it is to detect in its early stages, especially in established and traditionally stable democracies. This new form of backsliding, characterised as constitutional rather than democratic backsliding, requires a rethinking of existing theories of democratic and constitutional self-defence. In the dissertation, a minimalist theory of militant constitutionalism is developed that might help slow backsliding. This dissertation offers a first systematic exploration and conceptualisation of militant constitutionalism, incorporating both theoretical and empirical viewpoints.

• Militant
• Constitutionalism: Democracy
• Rule of law
• Constitutional backsliding
• United Kingdom
• Militant Constitutionalism
• Judicial review
• Empirical legal reserach

• All authors: Manenschijn, J.I.
• Supervisor: Ellian, A.
• Co-supervisor: Molier, G.
• Committee: Rijpkema, B.R.; Hartendorp, R.C.; Voermans, W.J.M.; Leijten, A.E.M.; Mak, E.
• Qualification: Doctor (dr.)
• Awarding Institution: Institute for the Interdisciplinary Study of the Law, Faculty of Law, Leiden University
• Date: 2026-02-13