I argue for the conditions that eco-sabotage (sabotage involving the protection of animals or the environment) must meet to be a morally permissible form of activism in a liberal democracy. I illustrate my case with Jessica Reznicek and Ruby Montoya’s oil pipeline destruction, the Sea Shepherd Conservation Society’s whale hunt sabotage, and the Valve Turners’ pipeline shut-off, climate necessity-defense. My primary contention is that just as it is permissible to destroy an attacker’s weapon in self- or other-defense, it is permissible (...) to engage in some forms of eco-sabotage. Taking inspiration from just war theory, I use the conditions of just cause, reasonable chance of success, proportionality, necessity, and discrimination to both conceptualize eco-sabotage as defense and illustrate the justificatory burden the eco-saboteur must meet. Often eco-sabotage is doubly pro-tanto wrong because it is illegal and involves property destruction. Overcoming these hurdles is particularly difficult because in seemingly bypassing democratic means of dispute resolution, the eco-saboteur seemingly coerces the other members of society by forcing idiosyncratic views upon them. Non-anthropocentric eco-sabotage grounded in defense of animal rights has mixed results regarding the democratic objection just described. I argue that anthropocentric eco-sabotage, grounded in defense of human rights, has the best chance of overcoming this objection, provided a persuasive case can be made for its reasonable chance of success. Passing a reasonable chance of success also causes problems for non-anthropocentric eco-sabotage grounded in species defense, while non-anthropocentric eco-sabotage grounded in defense against animal suffering has a lighter justificatory burden. (shrink)