This contribution explores the key challenges of contemporary EU policies that shape and can contribute to explaining the EU’s foreign policy and diplomacy in the fields of neighbourhood policy and accession as well as migration policies, and, notably, its responses to the 2015/2016 migration and refugee crisis. It analyses how social unrest, uprisings and wars in the Middle East, Northern Africa and Eastern Europe, the rise of terrorism and Jihadism, the refugee crisis as well as inequality within the EU fuelled the rise of illiberal, anti-EU and anti-immigrant sentiments, resulting in a security crisis, ruptures between EU member states and subsequently a crisis of the European project and thus the postwar European peace project. It argues that stabilising and protecting the EU overrides all other policy considerations. This priority subsequently also informs EU foreign policy vis-à-vis Turkey.