An effective nuclear deterrent is very low cost compared to an effective conventional military force. With nuclear weapons you can credibly threaten to kill 20 million people in $enemy_country [1] at a cost smaller than that needed to maintain a crewed air force of moderate capability. In theory, global military spending could drop by 90% with equal-or-better prevention of state-on-state warfare if more nations replaced conventional military spending with spending on nuclear weapons.
Unfortunately, nuclear deterrence only works against rational actors, by rational actors. It doesn't prevent irrational human behavior or accidents. So a heavily nuclear armed world would probably see a downturn in violence between states until one fateful year when an accident or miscalculation escalates to kill more people than every war of the past 200 years combined.
[1] Terms and conditions apply: only valid for countries with population greater than 20 million.
Unfortunately, nuclear deterrence only works against rational actors, by rational actors. It doesn't prevent irrational human behavior or accidents. So a heavily nuclear armed world would probably see a downturn in violence between states until one fateful year when an accident or miscalculation escalates to kill more people than every war of the past 200 years combined.
[1] Terms and conditions apply: only valid for countries with population greater than 20 million.