If interpretation of a legal norm under national law in conformity with international law indicates that the national law is in conflict with a directly applicable provision of international law, this gives rise to the issue of which has primacy and trumps the other rule. Legislators strive to avoid conflicts with international law. The relationship to international law is addressed by the Federal Council in its draft legislation and by Parliament in its parliamentary deliberations, although it is naturally not possible to foresee all cases of application and subsequent developments. In the case of popular initiatives aimed at amending the Federal Constitution, it occasionally remains unclear during the voting campaign whether the constitutional amendment violates international law if the issue is not addressed in the amendment itself – which it usually is not. The creators of the 1999 constitution were not aiming to conclusively settle the thorny question. Thus in the rare cases in which a conflict between national and international law become apparent, the Federal Supreme Court has to decide the issue of primacy in a case of application. The Federal Supreme Court rulings have always been favourable to international law without further justification of such finding other than the view that all state organs are obliged to voluntarily fulfil obligations entered into by the state (pacta sunt servanda; see for example BGE 21/1895, 705, 710). Exceptions in which the Federal Supreme Court upholds the primacy of national law are very rare. In BGE 59 II 331, the Federal Supreme Court ruled that international agreements only have the rank of law domestically, and conflicts must be resolved according to the principle of lex posterior derogat priori. The national law was more recent in the case reviewed, so it was seen as having precedence even though the international treaty was amended slightly later on.
In the seminal Schubert ruling (BGE 99 Ib 39), summarized below, national law was found to have primacy because legislators had willingly and knowingly taken the conflict with international law into account. The Federal Supreme Court has cited this ruling in later decisions without it having any practical implications. In one case, the national legal norm was applied while leaving open the possibility of a conflict with international law (BGE 112 II 1, 13).
A new situation arose when the ECHR entered into force in Switzerland in 1974 in respect of two characteristics of Swiss-style direct democracy.
It should be noted at the outset that the ECHR is equipped with a very effective enforcement mechanism. If the ECtHR finds in a complaint that a state party has violated a human right or fundamental freedom protected by the ECHR, the state is obliged to comply with the court’s decision. If the state fails to comply, the Committee of Ministers can take measures, which in most cases are effective. Swiss national law requires the Federal Supreme Court to revise a decision which has been successfully appealed to the ECtHR if doing so is necessary to remedy the infringement. Because the Federal Supreme Court thus ultimately has to decide in alignment with ECtHR decisions, it makes no sense for the former to rule in the first place by disregarding the established case law of the ECtHR. Unlike most other countries, Switzerland however has the democratic problem discussed that the Federal Supreme Court, as a matter of domestic law, does not enjoy the power to review legislative acts of the federal Parliament. (see Part I A. 2. on The Federal Supreme Court in Relation to Parliament, Part II D. on Constitutional Jurisdiction). This implies that as a matter of constitutional law a complaint cannot be brought before the Federal Supreme Court challenging a provision of a federal statute allegedly breaching the Constitution. As the freedoms and fundamental rights under the ECHR have been deliberately and democratically integrated into the catalogue of fundamental rights in the Federal Constitution of 1999 in terms of minimal guarantees. They were not part of the earlier Federal Constitution when Switzerland joined the ECHR in 1974. The fact that violation of these integrated minimal guarantees under the ECHR can be challenged before the Federal Supreme Court implies that a violation of the constitution can be litigated by indirect means. In its ruling on PKK propaganda material, a summary of which is provided below, the Federal Supreme Court upheld the priority of a legal norm of the ECHR, which in substance corresponds to a fundamental right under the Federal Constitution, over a federal law, taking into account the particular enforcement mechanism the ECHR. This ruling effectively introduced indirect powers of constitutional review, limited to the freedoms and fundamental rights as protected under the ECHR and other human rights conventions to the extent these guarantees are directly applicable and self-executing.
The Federal Constitution recognizes the right of popular initiative as a further characteristic of Swiss direct democracy. An amendment to the Federal Constitution may be called for by petition of 100,000 Swiss citizens entitled to vote. A proposed amendment must not violate provisions of compelling international law (jus cogens). If a majority of eligible voters and a majority of the cantons vote in favour, the Constitution is amended accordingly. In this situation too the Federal Supreme Court is responsible to decide about the primacy either the international legal norm or the Federal Constitution in a specific case of application. In BGE 139 I 116 the Court found that the ECHR provision takes precedence in the case.
Further change was brought about by the entry into force in 2002 of the so-called bilateral or sectoral agreements between Switzerland and the EU and its Member States. They entitle Switzerland to participate in certain sectors of the European internal market. The application of the Agreement on the Free Movement of Persons is particularly controversial in public debate and highly politised. In BGE 133 V 367, summarized below, the Federal Supreme Court for the first time upheld primacy of the Agreement on the Free Movement of Persons over conflicting federal statutory law in a very specific configuration of circumstances.
Further in BGE 142 II 35, summarized below, the Court built upon the earlier ruling, recognizing in an obiter dictum the primacy of the Agreement on the Free Movement of Persons over a conflicting constitutional provision which had been incorporated into the Constitution upon narrow approval of an initiative by the Swiss people and a majority of the Cantons. Parliament took this into account when adopting the necessary implementing legislation. Ultimately, the Federal Supreme Court remained true to the principle of pacta sunt servanda, even in these politically sensitive configurations. However, there have only been a few relevant rulings, so it is not yet conclusive to speak of established case law. The jurisprudence and case law of the federal courts was strengthened when a popular initiative massively failed to pass in a 2018 referendum vote by 66 %. The failed amendment explicitly poposed and stated that national law takes precedence over international law under the Federal Constitution.