Europe is in peace to a great extent. Wars, which can have states fall victim to aggressions endangering the national existence, have become more or less unlikely. This is the one great achievement for peace of the EU, and it received the Peace Nobel Prize for it. This achievement, however, would hardly have been possible, if American troops had not been present since the end of the Second World War for 68 years now. Their presence gave protection against outside and settled tensions among the states of Europe. Today, the topic of defence does not have any relevance in public discussions any longer. Even the USA have become influenced by this mood and are aware of the fact now that that they are and will be the only law enforcement agency of the world, although they will probably not intervene for the sake of Europe, as they did three times in the past century. Perhaps historians will talk about the Obama Doctrine later on in the 21st century: „Europe to the Europeans“. Naturally, there are many hazards threatening Europe, but they cannot be described directly, they are hard to impart, and seldom of a military nature. Thus, the question is not only relevant in Switzerland: What does defence mean in the 21st century? - Even if the Swiss have just confirmed their compulsory military service quite impressively. Maybe here, however, this question is even more insistent, because it is to be answered on a national level, whereas NATO and EU member states can refer to international assessments and obligations when justifying their defence efforts. Strategically, Germany as well as the NATO will remain aligned for defence. For Germany, this already results from the regulations in Article 26 GG “Ban of war of aggression”. Strategic defensive, however, does never also mean to waive the capability to act offensively on the operational level. This implies establishing armed forces, training and commanding them when deployed, quickly disposable, highly mobile, deployable everywhere, and geared towards a spectrum of tasks reaching from intensive fighting under the conditions of „information warfare“ to humanitarian assistance, capable of sustaining for longer periods of time. For the security forces, armed forces, police, intelligence services and disaster control, this means close cooperation and the capability of taking over all tasks ensuring public order in regions without functioning politic bodies. Today, defence necessitates an integrated system of all security forces as well as command and control which acts swiftly, inter-ministerially, including the entirety of the state, reaching from protection in humanitarian emergencies and natural disasters, the fight against organized, even internationally organized crime, to the repulse of and protection against impacts of NBC-weapons, air attacks and cyber attacks. All European states have to face these tasks, and they have to inspect their national forces and organisations accordingly and, if necessary, improve them.