Vertical Comparative Law Methods: Tools for Conceptualising the International Rule of Law

International institutions are increasingly engaged in the exercise of public power – traditionally exercised by states – that might adversely affect individuals. Consequently, calls have arisen for checks and balances in order to provide affected individuals with adequate avenues for recourse and redress. Developing the ‘rule of law’ concept at the international level is one way in which this issue has been addressed, although only to a limited extent. This article explores the potential of comparative law methodology as a means to further this conceptualisation. It is argued that ‘vertical, bottom-up’ comparative law methods (as expounded by this article) can assist lawyers inspired by certain concepts within national legal systems (such as the rule of law) to apply these concepts – or the ideas behind them – at the international level. Furthermore, it is argued that employing comparative law methodology in this manner is increasingly justifi ed by the emergence of a ‘common zone of impact’ – i.e., the area of overlap between national and international law, where individuals are adversely affected by the exercise of public power by states and international institutions alike. The authors propose a comparative law typology and discuss what risks might typically be involved in employing comparative law methods in general, as well as ways in which these risks could potentially be mitigated. Specifi cally, the article sets out a particular vertical, bottom-up comparative law method, as employed in the context of two separate doctoral research projects, both focusing on ways to enhance the accountability of international institutions: one in the context of international territorial administrations, and the other in the context of the World Bank and its Inspection Panel.