If you value the existence of your own civilization then the only winning strategy to answer to a nuclear threat is counter threat with MAD. You have to be will

If you value the existence of your own civilization then the only winning strategy to answer to a nuclear threat is counter threat with MAD. You have to be willing to go to the end with this. You really have to be willing to destroy yourself to destroy the one that is threatening you. There is no way around this or you loose everything.