 As is true for homeowners today, everyone would be responsible for buying or otherwise being covered by aggression insurance in order to protect themselves against catastrophic loss from foreign attack; in the event of an invasion, a claim would be filed with right of subrogation, and the insurer would hire a private defense company to collect from the aggressor.An argument against this method of funding is that other aggression insurers who didn't pay for defense would still benefit from the reduced risk of attack on their customers in the same area, in effect becoming free riders who could drive the "altruistic" insurer out of business.However, the private defense agency's activity need not be limited to defensive and retaliatory measures funded by the insurer; It could also go after the aggressor in an effort to obtain restitution (including reasonable collection costs), perhaps through ransom or capture of enemy assets, as privateers did in the 18th and 19th centuries under letters of marque and reprisal.