Last week Joost Taverne, Member of Parliament for the Dutch liberal party (VVD), introduced a bill in parliament to change the constitutional provisions on the incorporation of international law into national law. The Netherlands has, by and large, a 'monist' system of incorporation, meaning that provisions in international treaties that have 'direct effect' can automatically be invoked by citizens before a judge. Many other countries apply a 'dualist' system, whereby a national law must explicitly incorporate the international provisions before citizens can rely on them.

Most civil and political human rights satisfy this 'direct effect' criterion. If the Dutch legislature would prohibit same-sex marriage, this could be challenged before a Dutch court on the grounds that it constitutes a breach of Articles 8 (respect for family life), 12 (right to marry) and 14 (non-discrimination) of the European Convention on Human Rights (ECHR). A judge would then have to determine whether these articles do in fact entail the right to same-sex marriage. He will review the text of the Convention, its legislative history, and case law of the European Court of Human Rights on the issue. If the judge reaches a positive conclusion, the Dutch law would be declared inapplicable and gay people retain their right to marry. Treaty review is especially relevant as the Dutch constitution (Article 120) prohibits the constitutional review of primary legislation. A law banning same-sex marriage could therefore not be challenged as a violation of Article 1 of the constitution (non-discrimination). Dualist countries often have a system of constitutional review (Germany), and some countries have a mixed system (United States). Only in a few democracies does the legislature have full sovereignty over the laws it can pass without any judicial review whatsoever, even if human rights violations are evident.

Treaty review cases seldom occur and are mostly limited in scope. The legislative memorandum thus justifies the new bill in a rather principled way. The Taverne bill does not question the hierarchy between international and national law. But for the interpretation of international human rights norms, and their application in concrete cases, one needs a "thorough understanding of the background of the norms," according to Taverne. He continues: "Judges lack the knowledge and expertise [to examine a law for compatibility with the treaty]. [...] International norms are established in a multilateral process, in which a compromise is found between different legal convictions, diplomatic relations, political beliefs and international interests. It is virtually impossible for a judge to take all these aspects into account when giving his opinion." Taverne considers the legislature more suitable for this job. When it considers new legislation, it has to (either implicitly or explicitly) examine a law's compatibility with international obligations. For a judge to review this would drag him into "a debate that is essentially political in nature."

Countries apply different systems of interaction between international and national law, and have different perspectives on the merits of treaty and constitutional review. But human rights are legal norms, and not mere political issues. Even if the Netherlands were to ban treaty review by its own judges, Dutch legislation would still need to pass the test of judges in Strasbourg and human rights committees in Geneva. The VVD proposal is based on a wrongful characterization of international law and the international legal system, which is somewhat cynical in a proposal that defies judges for their lack of knowledge and expertise. A debate on treaty review is worth having, but the VVD proposal is a false start.