My research concentrates on the rule of law in Europe. More precisely, I focus on how the law can protect individuals against unlawful acts by public authorities. I examine legal arrangements and ways of thinking by lawyers and policymakers that may promote or hamper individual legal protection.

My approach is typically as follows. I first identify and analyze legal arrangements or ways of thinking that compromise individual legal protection. Then I look for alternative legal arrangements or legal concepts already present in existing law offering more legal protection but which happened to be overlooked by most jurists. In other words, when trying to find remedies for lagging legal protection I try to draw as much as possible on the logic of existing law by relying on legal doctrine, legal theory and legal history, rather than on moral philosophy or political theory.

In my research I look mainly at migration law and policy of the EU and its Member States. The underlying idea is that how the law treats migrants is also a good indication of how the law treats its citizens. Accordingly, the insights from my research are often not restricted to the legal protection of migrants but may say something about the rule of law in Europe in general.

My publications typically combine the following three legal fields: immigration and asylum law, administrative law and legal theory.

Exclusion of Immigrants. I have argued for a fundamental change in European admission laws and policies: when denying migrants admission authorities must justify the exclusion vis-à-vis the excluded migrant. The authorities must carry the first burden of justification and must show that exclusion is the least burdensome measure available to achieve their policy goals.

Refugee Protection. Common European Asylum System. I have analyzed historical arrangements offering protection to refugees, namely church asylum in the Middle Ages and refuge for religious minorities. From this analysis followed that  a basic condition for the legal protection of refugees is the existence of multiple jurisdictions, which in turn caters for competition for jurisdiction. By contrast, such competition for jurisdiction is missing under the current European refugee system that operates as a ‘single jurisdiction’ vis-à-vis the refugees. This partially explains why legal protection for refugees is lagging.

Frontex. Frontex has now its own border agents (3,000 in 2027). As a result it has its own operational powers. This poses a risk for individual legal protection of migrants at sea. The current protective mechanisms insufficiently address the factual and physical nature of Frontex’ new operational powers. Frontex can now physically act unlawfully – eg pushback operations. The current mechanisms of legal protection cannot address the factual and physical nature of Frontex' new operational powers. I argue that the EU must establish concrete physical and operational counterforces, for example independent agents who can immediately and physically intervene during Frontex operations and stop unlawful acts.

Migration Management. The official objective of the EU’s common immigration policy is “the efficient management of migration flows” (Art. 79 TFEU). The logic of this official objective goes against the logic of the rule of law, because ‘management of migration flows’ neglects a basic ingredient for legal protection of migrants: namely legal norms directed at individual migrants. The migration management logic has its precursor in ‘Policey’ and ‘la police’ which emerged as a new mode of governance in the 17^th and 18^th century. The latter also explains how migration law became a matter of administrative law.

Authoritarian Elements of Administrative Law. Contemporary regimes in democratic decay (e.g. Poland, Hungary) target and marginalize political opponents through legal measures. Scholars have overlooked the fact that most of these measures are matters governed by administrative law. I have shown that administrative law contains elements that enable illiberal tactics that would not have been possible under civil and criminal law. Moreover, not only regimes in democratic decay but also liberal democracies make use of administrative law for illiberal practices that are not possible under civil and criminal law.

Migration Law as Administrative Law. The lagging legal protection of migrants is not so much a problem of too little human rights protection, but rather a problem of too much administrative law. The precarious legal position of migrants is largely due to the fact that the legal position of migrants is predominantly governed by administrative law.

Legal Theory and Legal Protection. In order to promote individual legal protection one must first understand the nature of protection and its lawlike character. To this end I explore in my research the different forms and modalities of protection. I also examine what is so distinctively legal about legal protection, compared to other normative and argumentative practices and systems (e.g. politics, morality, economics, etc.). In this context I discuss the communicative structure of law: people invoke the law in order to seek cooperation from others that ultimately may consists in forms of coercion, or at least factual actions. Though coercion and factual actions are the ultimate goal, law itself is matter of verbal invocations. It means that legal protection is also first of all a matter of verbal invocations. This communicative structure of law helps us better understand the conditions and circumstances that hamper or promote individual legal protection.