So what do you do if your neighbor decides to take you computer from your own house ? What nation should do if another nation decides to impose tariffs on reso

So what do you do if your neighbor decides to take you computer from your own house ? What nation should do if another nation decides to impose tariffs on resources that does not belong to them ? Army is about readiness to use directed violence to stop people/organization/nations taking what does not belong to them, there also support functions related to emergency services in case of natural, technological or other emergency situations. People who never experienced emergency situations, don't even think about what they would do and how they should they be prepared in case of fire in there own house. State of safety and security processes is taken for granted, unfortunately, by most people.