De Haas argues that restrictive European immigration policies have generally failed to reduce migration flows from Africa because they do not address the underlying structural demand for labour in European states. Dirk Kohnert argues that EU countries' policies on migration from Africa are focused mainly on security and the closing of borders. He is also skeptical that the EU's programmes that are designed to promote economic development in West Africa will result in reduced migration. Stephen Castles argues that there is a "sedentary bias" in developed states' migration policies towards Africa. He argues that "it has become the conventional wisdom to argue that promoting economic development in the Global South has the potential to reduce migration to the North. This carries the clear implication that such migration is a bad thing, and poor people should stay put". Julien Brachet argues that while "irregular migration from sub-Saharan Africa to Europe is very limited in absolute and relative numbers", "none" of the European migration policies implemented in northern and western Africa "has ever led to a real and sustainable decrease in the number of migrants" travelling towards Europe, but they have "directly fostered the clandestine transport of migrants".