The Foreign Office civil servant Sir Eyre Crowe also wrote a memorandum to the British cabinet claiming that "a solemn league and covenant" would just be "a treaty, like other treaties". "What is there to ensure that it will not, like other treaties, be broken?" Crowe went on to express scepticism of the planned "pledge of common action" against aggressors because he believed the actions of individual states would still be determined by national interests and the balance of power. He also criticised the proposal for League economic sanctions because it would be ineffectual and that "It is all a question of real military preponderance". Universal disarmament was a practical impossibility, Crowe warned.