Since 2013, combat services have been increasingly exchanged on the market. This development is puzzling since the practice emerged despite an anti-mercenary norm banning such services, and without any revision of the norm. The article argues that the combat market is not a deliberate design, but the result of strategic interaction. For some, compliance with the anti-mercenary norm is the best strategy, while for others, violating the norm is best. However, once the norm violation occurs, it is in the interest of all actors to maintain a façade of compliance. Non-compliant actors benefit from the combat services, and compliant actors do not have to engage in costly sanctioning of the norm violation, and avoid the reputational costs associated with non-enforcement. The article employs game theory to investigate the strategic interactions of actors across 11 combat contracts from 2013 to 2019.