The US was never been invaded from the time it became a nation, without nukes. North Korea forced an end to the war they arguably started with help from the CCCP, and were not invaded afterwards, again without a nuclear deterrent. European politics are…historically complex and putting a finger one one element- nuclear weapons- as the core reason for post WW2 stability is overly simplistic.

Saying that nuclear weapons “only need to be in working order” is another oversimplification. Maintaining and protecting a nuclear arsenal requires not only huge amounts of money, educating people to be qualified to do so, maintaining a security apparatus to protect that arsenal, but also a system to develop, evaluate and effect upgrades to aging systems. Let’s not leave out the incidental costs of having these weapons around, like poisoning of individuals and communities, which also need to be considered in a full accounting. If you leave out the most important costs and only list “there might be a monster under my bed…someday”, that’s not a valid cost benefit analysis.