Stateless nutters with a suitcase of sunshine are one threat. Nuclear-armed states that may not entirely follow the happy-clappy agenda are another.
You can never deter a stateless nutter with anything. If you are really lucky his sponsor (if a state) might just think twice.
You can (hopefully) deter the nuclear-armed state, provided that he is convinced that :
a) He can't find and neutralise your delivery system
b) Once the weapon is on the way, he's toast - with no escape route.
The further away and faster you can deliver the good news, the more convincing that deterrent is. Given that one of the (currently) more unfriendly nuclear armed states is still the one trident was specified against, difficult to see why we should go for anything less.
So that's a "yes" then.