Question

Good afternoon!
1. According to the Torah, is it permissible to strike in a preventive war in order to deter a potential enemy, or only when it is self-defense?
2. What counts as self-defense under the rule of “if someone comes to kill you”? For example, in the Middle East, if people know not to mess with Israel, is that considered self-defense, or only deterrence? (Maybe this is related to the discussion in Noda B’Yehuda about studying medicine by desecrating a corpse in order to save lives in the future, and on the other hand extinguishing a property fire on the Sabbath because of a possible risk to life? Or perhaps here the harmful act has already begun?)
Thank you very much!