Proportionality analysis is considered a central tool for rights adjudication in contemporary constitutional law. Prevailing academic narrative explains its worldwide spread as a matter of legal migration. This chapter challenges this narrative through the analysis of Argentine constitutional practice. It reconstructs the different variants of proportionality scrutiny that have been applied by the Argentinian Supreme Court from the beginnings of the twentieth century, well before the development of the modern proportionality test by the German Constitutional Court, and surveys its role in the adjudication not only of civil and political rights but also social rights. It ultimately argues that constitutional practices in this domain are better explained under a paradigm of interaction, rather than under one of migration.

Wojciech Sadurski considers how the European Court of Human Rights (ECtHR), an emerging European constitutional court for human rights, has engaged in a public reason compatible scrutiny of legislative aims pursued by national laws interfering with the proclaimed rights. Sadurski concludes that the Court has almost always eschewed its authority to evaluate the aims of state laws or decisions in this way. On the very few occasions when it did express its doubts about the plausibility of the aims cited by the governments concerned, the Court either refused to attach any weight to these doubts and moved on to the next stage in the analysis (the necessity scrutiny). The main burden of the aim scrutiny was therefore shifted to the necessity stage, when the Court assessed whether the restrictions were necessary (in a democratic society) to attain this aim. Sadurski offers an explanation for this puzzling (as he claims) argumentative maneuver. Challenging the state at stage of aim ascertainment brings the Court into a head-on collision course with the state and risks weakening the Court’s legitimacy, which is tenuous at the best of times anyway.

The chapter develops a Kantian account of constitutional justice: the explication of those structural features of a legal system whose purpose is to optimize a polity’s capacity to achieve a Rightful condition. The People, in enacting a rights-based constitution, have placed their freedom in trust. Rights ground a system of reciprocal freedom among individuals, while conferring on officials the authority to make and enforce law, subject to constraints laid down by the Universal Principle of Right (UPR). A constitutional court, the trustee of the regime, supervises the rights-regarding acts of all other officials, assesses the reasons officials give when they make decisions that burden rights, and invalidates those acts when reasons given to justify such burdens fail to meet the demands of the UPR. Although some rights will be expressed in absolute terms, most will be qualified by a limitation clause. In adjudicating qualified rights, the court can do no better than to adopt the proportionality principle. The UPR, operationalized through proportionality analysis, lays down a basic criterion for the legitimacy of all law.

The right to justification (RTJ) is borrowed from moral and political theory to offer normative guidance in the concrete and localized circumstances of the proportionality test. Based on the seminal work of Rainer Forst, Mattias Kumm has illustrated in various pieces how the RTJ operates in the proportionality context by identifying “excluded reasons” for limiting rights. However, Kumm does not clearly explain if the test also helps identify what the RTJ positively requires. This chapter aims to remedy this deficit in three steps: (1) present the core features of Forst’s account of the RTJ and emphasize the right that best demarcates the RTJ from rival accounts of human rights, namely the right to democratic participation; (2) reconstruct the precise role that the RTJ should play in proportionality analysis as suggested by Kumm, which the author insists on the common thread between Forst and Kumm, namely how the principle of mutual justifiability should inform the evaluative part of the proportionality test; and (3) show how the RTJ can help to balance two equally protected rights, expression and privacy, by reference to the practice of the European Court of Human Rights.