As a member of Nato, Sweden is to actively take part in Nato’s deterrence activities. The concept of deterrence is that one actor persuades a would-be aggressor that an aggression would incur a cost, which would far outweigh any potential gain, material or political. By demonstrating presence, cohesion and capability, an aggressor is deterred from even thinking about attacking a Nato member state. For example, capability may be demonstrated by a joint flyover of a certain area. Nuclear weapons is the ultimate tool of Nato deterrence.