The annexation of Crimea by Russia and the subsequent war in the Donbas have delivered a severe blow to the European security order, and have increased tensions between the West and Russia to a level unprecedented since the end of the Cold War. In this context, it would be difficult to start negotiating a new commitment to the principles of the European security order. In this Policy Brief, Paul Ivan analyses the Ukraine crisis and its effect on European security and calls for the EU and NATO to stand firm on their own principles, but also to engage carefully with Russia to develop mechanisms to contain risks and avoid escalation and military confrontation, whether in Syria, the Baltic, the Mediterranean or the Black seas. The recent shooting down of a Russian jet by Turkish forces makes clear the need to prevent such incidents with potential rapid escalatory dynamics.