Individuals who commit crimes often have support from family or community members who benefit from the illegal profits. Holding families or groups liable could help deter crimes like terrorism by providing incentives for internal monitoring. There are two rationales for group liability: 1) target the constituency that benefits, similar to vicarious liability, or 2) identify superior enforcers since groups can monitor members more effectively. Imposing liability on families or groups could lower enforcement costs for the government by delegating monitoring responsibilities, but it also increases monitoring costs for local groups. An economic model of group liability may help address crimes and terrorism with consideration of internal and global contexts.