It is an almost impossible question to answer, and there are many reasonable ones given already, yet for me, one stands out clear of all others, and that was made by perhaps the most brilliant scientist of the last 100 years – John von Neumann when he gave us “Mutually Assured Destruction”.
We have managed to survive it, but it has been a very close thing on several occasions, and we have only survived because individuals within the systems refused to follow the system and do what the system required of them (destroy technological humanity).
The only thing wrong with the strategy is that it is founded on invalid assumptions; an insufficient depth of understanding of the strategic complexity of our evolutionary history. As such it has put us in a very high risk scenario (much higher than it needs to be).
And this is not a simplistic call for a one sided disarmament, but rather a call for a fundamental restructuring of global policy based on cooperation, individual rights and responsibilities and acceptance of diversity rather than of competition and holding to “norms”, and with sufficient systems in place to have a reasonable probability of detecting and removing any level of “cheating strategy” – which requires ongoing search effort through the space of all possible strategies.