Table of Contents: I. Introduction. – II. Horizontal federalism in the US. – II.1. Full faith and credit. – II.2. Extradition. – II.3. Interstate commerce. – II.4. Interstate compacts. – III. Horizontal federalism in the EU: mutual recognition. – III.1. Constitutional principle by accident? – III.2. Apogee and after. – III.3. Mutual recognition, harmonization and national autonomy. A decision making triangle. – IV. Conclusions.
Abstract: The – vertical – relation between the central level and sub-central levels of government is a key issue in federal-type systems, including the EU. A question which usually attracts much less attention is how the – horizontal – relations between the sub-central levels are shaped. In this contribution, the legal arrangements in the US and EU legal orders to shape the horizontal relations between the (Member) States (“horizontal federalism”) will be analysed and compared. Whereas the US legal system contains a variety of arrangements, the EU relies rather exclusively on the principle of mutual recognition. The central question is how legal arrangements of horizontal federalism balance harmonization (or control by the central/federal level), recognition and acceptance of foreign rules and (host) State autonomy. From the perspective of the host (Member) State, the question is thus to what extent it may apply its own rules (host State autonomy) or whether it must comply with central rules (harmonization) and foreign rules (from other States). This article examines how this balance is struck in different policy fields, what mechanisms are applied (especially in the US context) and which factors determine the choice for a particular balance.
Keywords: mutual recognition – horizontal federalism – full faith and credit – State autonomy – Area of Freedom, Security and Justice – internal market.
* Associate Professor, Utrecht University, firstname.lastname@example.org.