This article discusses the implementation of the Water Framework Directive (WFD) in the Netherlands and shows how law and politics combine in river basin management. Initially, the implementation of the WFD in the Netherlands was approached as a technical and administrative issue, handled by water quality and ecology experts, but, in 2003, this approach was broken open by the agricultural sector, who feared stricter regulation. Subsequently, the environmental objectives of the WFD were set as low as possible and they play no role when authorising new projects. In July 2015, however, the European Court of Justice determined that the environmental objectives have a binding effect and that Member States have to refuse authorisation of projects that jeopardise the achievement of these objectives. This example shows the important role that law as a social phenomenon or “field” can play in river basin management, provided the courts enjoy sufficient social and political support and function relatively independently, as they do in the Netherlands. The article discusses the origin of the juridical field and its relation with politics and concludes that, to understand river basin management fully, it is essential to understand how (water) law functions.