If Plutonia detonates its weapons outside its own territory offensively then the target is either nuclear-armed or non-nuclear armed.
If the target is nuclear-armed then the target state can be expected to retaliate with overwhelming force, thus removing the Plutonian government from power.
If the target is not nuclear-armed then nuclear armed states may or may not retaliate with overwhelming force. Exactly what happens here depends on what country Plutonia really is[1], who the target of the nuclear strike is and other geopolitical conditions.
Either way, the danger Plutonia poses to the rest of the world is eliminated before things can snowball.
How the world would respond to a nuclear first strike by Russia is very different from a nuclear first strike by North Korea is very different from a nuclear first strike by Iran.
The problem is that retaliation is not immediate (missiles takes few hours to reach the goal). For example, Plutonia can demonstratively destroy one object and declare that any attempt of retaliation will be retaliated in double. As soon as other country launches N missiles, Plutonia launches 2 N.
If Plutonia detonates its weapons outside its own territory offensively then the target is either nuclear-armed or non-nuclear armed.
If the target is nuclear-armed then the target state can be expected to retaliate with overwhelming force, thus removing the Plutonian government from power.
If the target is not nuclear-armed then nuclear armed states may or may not retaliate with overwhelming force. Exactly what happens here depends on what country Plutonia really is[1], who the target of the nuclear strike is and other geopolitical conditions.
Either way, the danger Plutonia poses to the rest of the world is eliminated before things can snowball.
How the world would respond to a nuclear first strike by Russia is very different from a nuclear first strike by North Korea is very different from a nuclear first strike by Iran.
The problem is that retaliation is not immediate (missiles takes few hours to reach the goal). For example, Plutonia can demonstratively destroy one object and declare that any attempt of retaliation will be retaliated in double. As soon as other country launches N missiles, Plutonia launches 2 N.