Article 42(7) TEU is the European Union’s mutual assistance clause. Once activated by an attacked Member State, all other Member States have to provide assistance in response. The article thus guarantees solidarity amongst Member States in case of an armed aggression against any one of them. This assistance can, for example, range from diplomatic support and
technical or medical assistance to civilian or military aid, among others. Member States have regularly held table-top and scenario-based exercises on the activation and implementation of the mutual assistance clause. These exercises also cover hybrid scenarios or large-scale cyberattacks. Article 42(7) TEU is consistent with commitments under NATO, which is and
will remain the foundation of collective defence for its members.