But if a treaty of reduction of armaments could be secured by such a guarantee of collective force, it would still find itself confronted by the problem of the lawless outsider. So long as an aggressive outsider were at liberty to threaten or coerce a member of the League without involving the hostility of the other members, this danger would compel members of the League to maintain large armaments, though they were secure against internal hostility. A single Power, such as Germany, Russia, or Japan, standing out for its absolute right to determine its own expenditure and policy, would cancel nearly all the economy of the agreement. It would become self-evident that the Powers entering such an agreement must bind themselves to a common defense against such an outsider. They would be impelled to this course by a double motive. In no other way could each member gain that security which would win his consent to a basis of reduction that would lower his separate defensive power. Again, by pledging themselves to united action against an aggressive outside Power, they would diminish, perhaps destroy, the aggressive design or policy of such a Power. For such aggressive policy and the armed force which supports it are only plausible upon the assumption that they can be successfully applied to gain a selfish national end. If the united strength of the Treaty Powers remained so great as to render the pursuance of its aggressive designs impossible or too dangerous, the lawless Powers might learn the lesson of the law, and, abandoning its hopes of aggression, come into the League. [Sidenote: Reduction must be linked with reversal of motives.]