In Switzerland, national and international law constitute a single, integrated order. If a provision of international law is binding on Switzerland, it automatically acquires domestic validity. However, before an international legal instrument is ratified, the Federal Council checks whether the provisions it contains correspond with national law. If there is not the domestic political will to adopt certain provisions of the instrument in question, in most cases Switzerland is entitled to make reservations.

As soon as Switzerland has accepted a body of international law, it becomes part of Swiss national law, and all state bodies must comply with, and apply the new provisions. The single legal concept – unlike the dual – does not require a provision of international law to be incorporated into national law by means of an additional act of parliament, such as a new law. Democratic rights are safeguarded through the referendum held on the treaty in question.

 
The Federal government and the cantons are required by the Swiss Constitution (Article 5, paragraph 4) to observe international law. However, the constitution makes no provision for cases of conflict between provisions of national and international law. Fundamentally, international law takes precedence. This arises from the obligation to fulfil treaties in good faith (1969 Vienna Convention on the Law of Treaties, article 26, link inserted). According to the Federal Council’s message on the Swiss Constitution, all state bodies must ensure that their actions comply with Switzerland’s international obligations. In its latest findings the Federal Court confirms without reservation the principle of the precedence of international law over national law (see Federal Court decision 125 II 417, p. 424f. or 128 IV 201, p. 205f.).

 
Not all provisions of international law have the effect of creating rights and duties directly. In order to do so, they must be properly formulated with the requisite degree of precision. International law that is not directly applicable or "self-executing" is generally of a programmatic nature – i.e. it is primarily up to national legislatures to implement it.

The Federal Court has devised criteria for deciding whether a provision of international law is directly applicable or not (see Federal Court decision 124 III 90 or 129 II 249, p. 257):

• The provision relates to the rights and duties of the individual.
• The provision is justiciable, i.e. sufficiently concrete and clear to be applied directly to a legal issue by an authority or a court.
• The provision is aimed at authorities that apply the law, not at legislatures.

Popular Initiatives and International Law 

Those popular initiatives which do not respect the binding rules of International Law (e.g., the prohibition of slavery or of torture) are, according to the present Swiss Constitution, declared null and void by the Federal Assembly. On the other hand, those popular initiatives whose non-conformity with other norms of International Law is not excluded are declared valid and submitted to the vote of the Swiss population and cantons. In the absence of the possibility of interpreting such initiatives in a manner conforming to International Law, Switzerland runs the risk of subsequently being obliged either to forego the application of Constitutional Law, or to violate its international commitments. 

In view of the above and in order to make an overall improvement in the compatibility of popular initiatives with International Law, the Federal Council suggests the two measures published in its 30 March 2011 Report dealing with this issue: 

• First: a material control to be conducted jointly by the Federal Department of Justice and Police (FDJP) and the Federal Department of Foreign Affairs (FDFA). On the part of the FDJP, this examination will be led by the Federal Office of Justice, while the Directorate of Public International Law will act on behalf of the FDFA. According to this model, the authors of the initiative would receive, prior to the gathering of signatures, a non-binding opinion on the compatibility of their text with International Law. Should the need arise, they would be able to adapt the initiative in such a way as to guarantee its conformity. The results of the material control would be indicated on the signature-list forms, thus enabling Swiss citizens to make a decision whether or not to support the initiative with full knowledge of the facts (informed choice).
• Second: a moderate expansion of the criteria according to which popular initiatives are declared invalid. This measure would make it possible to declare initiatives as null and void not only when they violate the binding rules of International Law, as is the case today, but also when they are not in conformity with the essence of Switzerland’s basic constitutional rights (e.g., the prohibition of capital punishment).

Parliament has accepted, in spring 2012, two motions requesting the Federal Council to submit a legislative act containing these two measures.

Moreover, the Federal Council draws the attention of the Swiss Legislature to the subsidiary possibility of envisaging the prohibition of discrimination as one of the material limits of popular initiatives in order to further contain the risk of conflict between popular initiatives and International Law.