The Subsidiarity Principle and Foreign Investors’ Participation in Treaty Negotiations as a Mechanism for Reinforcing the Rule of Law
DOI:
https://doi.org/10.25159/2521-2583/23483Keywords:
rule of law, subsidiarity principle, foreign investment, enforceability of international rules, international legal personalityAbstract
In recent debates, the narrative has been to secure and promote the rule of law at both domestic and international levels. As such, the international investment legal system may be advanced to justify and legitimise the existence and operation of the rule of law. The subsidiarity principle asserts that matters should be handled by the smallest, least centralised competent authority. In this article, I address the research question: How can the subsidiarity principle and foreign investor participation be strategically integrated into treaty negotiations to strengthen the rule of law within the international investment framework? I use a doctrinal research methodology to explore the interplay between the subsidiarity principle and foreign investor involvement as complementary mechanisms for reinforcing the rule of law in international investment negotiations. The subsidiarity principle, traditionally rooted in constitutional and administrative law, is examined in the context of global investment governance to assess its potential in empowering domestic legal institutions while maintaining coherence with international legal standards. Using the doctrinal and normative research methodology, I investigate how foreign investors can act as catalysts for legal reform and institutional strengthening in host states through treaties and corporate responsibility initiatives. I demonstrate that when the subsidiarity principle is operationalised alongside meaningful investor engagement, it can balance the negotiation power, enhance transparency, and promote legal predictability. The findings suggest normative mechanisms of participation where subsidiarity and investor participation are not merely procedural tools but strategic levers for embedding the rule of law in investment practices.
References
African Development Group, African Economic Outlook of 2024: Driving Africa’s Transformation (2028) Côte d’Ivoire: African Development Bank Group <https://www.afdb.org/en/documents/african-economic-outlook-2024>
African Union, ‘Regional Economic Communities’ (n.d) < https://au.int/en/recs>
Ali Said, Muhammad H Zakir, Ayesha Tasawar and Syed H Khan, ‘The Concept of State Sovereignty in International Law’ (2021) 2 Asian Social Studies and Applied Research.
Alvarez J, ‘Are Corporations “Subjects” of International Law?’ (2011) 9 (1) Santa Clara Journal of International Law <https://digitalcommons.law.scu.edu/scujil/vol9/iss1/1/>
Asante S, ‘The International Law and Foreign Investment: A Reappraisal.’ (1988) 37 The International and Comparative Law Quarterly <https://doi.org/10.1093/iclqaj/37.3.558>
Bingham T, The Rule of Law (Penguin 2011).
Brölmann Catherine and Janne Nijma, ‘Legal Personality as a Fundamental Concept for International Law’ (2016) 43 Amsterdam Law School Legal Studies <https://doi.org/10.2139/ssrn.2845222>
Burgess Liam and Leah Friedman, ‘A Mistake Built on Mistakes: The Exclusion of Individuals under International Law’ (2005) 11 Macquarie Law Journal.
Burke Roland, Marco Duranti and Dirk Moses (eds), ‘Introduction: Human Rights, Empire, and After’ in AD Moses, M Duranti and R Burke (eds), Determination, and the Rise of Global Human Rights Politics (Cambridge University Press 2020) <https://doi.org/10.1017/9781108783170.001>
Chesterman Simon, ‘An International Rule of Law.’ (2008) 2 The American Journal of Comparative Law https://doi.org/10.5131/ajcl.2007.0009
Choudhury Banali, Corporations as International Economic Law Actors. (2024) Encyclopedia of International Economic Law (Edward Elgar 2024) (Forthcoming) <https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4475474>
Commonwealth Local Government Forum, The Aberdeen Agenda: Commonwealth Principles on Good Practice for Local Democracy and Good Governance (Commonwealth Local Government Forum 2005).
Craig Paul, ‘Formal and Substantive Conceptions of the Rule of Law: An Analytical Framework’ in R Bellamy (ed), The Rule of Law and the Separation of Powers (Routledge 2017) <https://doi.org/10.4324/9781315085302-4>
D’Amato Anthony, International Law: Process and Prospect (Transnational Publishers 1995).
Damjanovic Ivan, ‘The Reform of International Investment Law: Whose Rule of Law?’ (2024) 15 European Journal of Risk Regulation <https://doi.org/10.1017/err.2024.28>
De Visser Jaap, ‘Subsidiarity in the Constitution: Slapstick Asymmetry or a Rights Based Approach to Powers?’ (2008) 10 Local Government Bulletin.
Dolzer Rudolf and Christoph Schreuer, Principles of International Law (Oxford University Press 2008) <https://doi.org/10.1093/law:iic/9780199211753.001.1>
Douglas Zachary, ‘The Hybrid Foundations of Investment Treaty Arbitration’ (2004) 74 British Yearbook of International Law <https://doi.org/10.1093/bybil/74.1.151>
Follesdal Andreas, ‘The Principle of Subsidiarity as a Constitutional Principle in International Law’ (2013) 2 Global Constitutionalism <https://doi.org/10.1017/S2045381712000123>
Fombad Charles M, ‘An Overview of the Crisis of the Rule of Law in Africa’ (2018) 18 African Human Rights Law Journal <https://doi.org/10.17159/1996-2096/2018/v18n1a11>
Franck Susan, ‘The Nature and Enforcement of Investor Rights under Investment Treaties: Do Investment Treaties Have a Bright Future?’ (2005) 12 University of California Davis Journal of Law and Policy.
Goldston A James, ‘Three Principles to Strengthen the Rule of Law’ (2012) Open Society Justice Initiative (25 January 2012) <https://www.justiceinitiative.org/voices/three-principles-to-strengthen-the-rule-of-law>
Garcia Luis G, ‘The Role of Human Rights in International Investment Law’ in N Jansen Calamita, D Earnest, and M Burgstaller (eds), The Future of ICSID and the Place of Investment Treaties in International Law (British Institute of International and Comparative Law 2013).
Gosepath S, ‘The Principle of Subsidiarity’ in A Føllesdal and T Pogge, Real World Justice: Grounds, Principles, Human Rights, and Social Institutions (Springer 2005). <https://doi.org/10.1007/1-4020-3142-4_9>
Henkel Christoph, ‘The Allocation of Powers in the European Union: A Closer Look at the Principle of Subsidiarity’ (2002) 20 Berkeley Journal of International Law.
Herdegen Matthias, Principles of International Economic Law (Oxford University Press 2013). <https://doi.org/10.1093/law/9780199579860.001.0001>
Kanetake M, ‘The Interfaces between the National and International Rule of Law: A Framework Paper’ in M Kanetake and A Nollkaemper (eds), The Rule of Law at the National and International Levels: Contestations and Deference (Hart Publishing 2016).
Lall S and Narula R, ‘Foreign Direct Investment and Its Role in Economic Development: Do We Need a New Agenda?’ (2004) 16 The European Journal of Development Research. <https://doi.org/10.1080/0957881042000266589>
LexisNexis, ‘The Rule of Law: What is the Rule of Law and Why is it Important?’<https://store.lexisnexis.com/en-ca/rule-of-law> accessed 15 October 2026.
Leonid A, ‘The Dimension of the Principle of Subsidiarity in the International Law of Human Rights.’ (2017) 2 Revista Institutului National Al Justitiei.
Lipson C, Standing Guard: Protecting Foreign Capital in the Nineteenth and Twentieth Centuries (University of California Press 1985) <https://doi.org/10.2307/jj.16430735>
Lööw L, ‘The Principle of Subsidiarity: An Examination of the Swedish Parliament’s Application of the New Protocol on Subsidiarity’ (Master’s diss., Uppsala University 2013).
Mavromati Ca and Spottiswood S, ‘Voices that Shape Investment Treaties: Inside, Outside and among States’ in C Citi (ed), Public Actors in International Investment Law. European Yearbook of International Economic Law (Springer 2021) <https://doi.org/10.1007/978-3-030-58916-5_1>
Mehranvar L and Johnson l, ‘Missing Masters: Causes, Consequences and Corrections for States’ Disengagement from the Investment Treaty System’ (2022) 13 Journal of International Law of Dispute Settlement. <https://doi.org/10.1093/jnlids/idac008>
Mhlongo LB, ‘The Effect and Impact of National and International Law on Foreign Investment in South Africa’ (Master’s diss., University of South Africa 2017 ). <https://doi.org/10.13140/RG.2.2.28927.05283>
Mhlongo LB, ‘Africanisation and Reformation of the African International Investment Landscape: Towards A New Continental Investment Agreement’ (Doctoral thesis, University of South Africa 2021) <https://hdl.handle.net/10500/29308>
Ming Du, ‘International Investment Law and the Rule of Law: The Case of China’ (2024) 33 Washington International Law Journal.
Oppenheim L, International Law: A Treatise. Vol. 1, Peace. (Longmans, Green, and Co 1912). (repr. 2012, Project Gutenberg).
Organisation of African Unity, Lagos Plan of Action for the Economic Development of Africa, 1980–2000 (April 1980, Lagos, Nigeria).
Perišiæ P, ‘Some Remarks on the International Legal Personality of Individuals.’ (2016) 49 Comparative and International Law Journal of Southern Africa <https://doi.org.10.10520/EJC200004>
Raz J, The Authority of Law: Essays on Law and Morality. (Oxford University Press 1979) <https://doi.org/10.1093/acprof:oso/9780198253457.001.0001>
Reich A, ‘Bilateralism Versus Multilateralism in International Economic Law: Applying the Principle of Subsidiarity’ (2010) 60 University of Toronto Law Journal <https://doi.org/10.3138/utlj.60.2.263>
Rubenstein DS, ‘Taking Care of the Rule of Law’ (2018) 86 George Washington Law Review.
Shaw M, International Law (Cambridge University Press 2009) <https://doi.org/10.1017/CBO9780511841637>
Swenson G, ‘Symbolic Rule of Law Promotion’ (2025) Law and Social Inquiry <https://doi.org/10.1017/lsi.2025.10127>
Tillmann RB, ‘Globalisation-Driven Innovation: The Investor as a Partial Subject in Public International Law. An Inquiry into the Nature and Limits of Investor Rights’ (2014) 15 The Journal of World Investment and Trade <https://doi.org/10.1163/22129000-01502003>
UNCTAD, 2026 World Investment Report: International Investment in a Turbulent Era. Geneva: United Nations <https://unctad.org/system/files/official-document/wir2026_en.pdf.> accessed 12 December 2024.
Waldron J, ‘Is the Rule of Law an Essentially Contested Concept (In Florida)?’ (2002) 21 Law and Philosophy <https://doi.org/10.1023/A:1014513930336>
Walter C, ‘Subjects of International Law’ in R Wolfrum (ed), The Max Planck Encyclopedia of Public International Law (Oxford University Press 2012). <https://doi.org.10.1093/law:epil/9780199231690/law-9780199231690-e1476>
World Justice Project (WJP) Rule of Law, ‘World Justice Project Rule of Law Index’ GovWatch (October 2024) <https://govwatch.gr/en/reports/world-justice-project-deiktis-toy-kratoys-dikaioy-2024/>
World Justice Project (WJP) Rule of Law, ‘The World Justice Project Rule of Law Index 2023’ GovWatch (29 October 2025) <https://govwatch.gr/en/reports/world-justice-project-deiktis-toy-kratoys-dikaioy-2025/>
Cases
Barcelona Traction, Light and Power Company, Limited (Belgium v Spain) (Second Phase) [1970] ICJ Rep 3.
Panevezys-Saldutiskis Railway (Estonia v Lithuania) (Judgement) [1939] PCIJ Series A/B No 76.
Pharmaceutical Manufacturers Association of SA: In re Ex Parte President of the Republic of South Africa [2000] (2) SA 674 (CC).
International Instruments
African Charter on Democracy, Elections and Governance (adopted 30 January 2007, entered into force 15 February 2012) AU Doc Assembly/AU/Dec.147(VIII).
Agreement Amending Annex 1 (Cooperation on Investment) on the Southern African Development Community (SADC) Protocol on Finance and Investment (signed 31 August 2016, entered into force 24 August 2017).
Agreement Establishing the African Continental Free Trade Area (adopted 21 March 2018, entered into force 30 May 2019).
Constitutive Act of the African Union (adopted 11 July 2000, entered into force 26 May 2001) 2154 UNTS 3.
European Charter of Local Self-Government (opened for signature 15 October 1985, entered into force 1 September 1988) ETS No 122.
Montevideo Convention on the Rights and Duties of States (signed 26 December 1933, entered into force 26 December 1934) 165 LNTS 19.
Reciprocal Investment Promotion and Protection Agreement Between the Government of the Kingdom of Morocco and the Government of the Federal Republic of Nigeria (signed 3 December 2016).
Southern African Development Community (SADC) Protocol on Finance and Investment (signed 18 August 2006, entered into force 16 April 2010).
Treaty Establishing the African Economic Community (signed 3 June 1991, entered into force 12 May 1994) 30 ILM 1241 (Abuja Treaty).
Treaty on European Union (Maastricht Treaty) [1992] (signed 7 February 1992) OJ C191/1.
United Nations General Assembly Universal Declaration of Human Rights (10 December 1948) Res 217 A (III).
United Nations Secretary-General. 2004. The Rule of Law and Transitional Justice in Conflict and Post-Conflict Societies. (23 August 2004) UN Doc S/2004/616.
Downloads
Published
How to Cite
Issue
Section
Accepted 2026-09-23
Published 2026-10-15