Zwart’s research focuses on issues related to human rights, courts (separation of powers), and public law from a comparative perspective. His publications in the area of human rights take as a point of departure the subsidiarity principle that is part of all major human rights instruments. It emphasises the need for a ‘bottom-up’ approach which stimulates the positive elements that already exist in every society, rather than forcing international norms on them ‘top down’. His Global Constitutional Justice project, which relies on such embedding of human rights, provides research support to constitutional courts in Central and Eastern Europe in the areas of comparative law and human rights. Northwestern University School of Law, Emory University School of Law, Vanderbilt University School of Law, the Russian School of Private Law and the Law Faculty of the University of Haifa are among the participants in this project.

Zwart is also in the process of setting up the so-called ‘matching values’ project, which looks for values in non-Western cultures, which can act as receptors for human rights principles. Underlying the project is the idea that non-Western cultures should neither be forced to accept human rights, nor be allowed to reject them out of hand as being ‘alien’. The project aims at by-passing the universalism versus relativism stalemate by seeking common ground between human rights and non-Western values. Several scholars and institutions, both in Africa and in Asia, have committed themselves to the project, including Tsinghua University in Beijing.