The provision of lethal aid to the Syrian rebels appears questionable from a purely legal perspective. It would arguably amount to a use of force. Neither of the traditional legal justifications for the use of force—self-defense and authorization by the Security Council—applies in this case. While humanitarian intervention arguably offers a (weak) basis for the use of force, states would be wise to hesitate before embracing a liberal right to humanitarian intervention, because such operations can serve as convenient subterfuges for armed intervention.