It is an offensive first strike weapon. It's primary purpose is mass destruction . I do not see how Trident can be used without falling foul of all legal principles. FB Not even for that, even then it still must comply with international law. Both the US and the UK have only big weapons.
Trident is designed for wanton destruction of towns and cities.
FB Tactical nuclear weapons had the explosive power of Hiroshima. When scientists moved to thermonuclear devices they could only be used for genocide. Britain has said that they might put a lower yield bomb on a Trident missile. JMc You are saying that the way that Trident II is used it is a threat. That's the whole purpose of targeting.