Not everything that is done is legal. What is not legal but is done anyway is often ignored or seen as grey areas. With the help of court decisions, a strict interpretation of the law leads to existing practices being transferred from being ignored to being relevant, with the result that existing (illegal?) institutional agreements and practices are no longer tolerated. Processes can be observed in which the combined resources of law, legal representation, and courts are used to promote steps towards discontinuation of environmentally harmful practices and infrastructures. These involve the mobilization of non-political means and ways to make governance and policy. The cases help to explore very different constellations and contexts, all with side-consequences that might lead to discontinuation. Before ageing systems can be shut down and declining technologies discontinued, their existence, maintenance, and use “as usual” must first be delegitimized. One way in which such work on discontinuation can proceed is presented here.