The great difficulty of all schemes for leagues of nations and the like has been to find an effective sanction against nations determined to break the peace.
I will not now discuss at length the difficulties of joint armed action, but every one who has studied the question knows they are very great. It may be, however, that a league of nations, properly furnished with machinery to enforce the financial, commercial, and economic isolation of any nation determined to force its will upon the world by mere violence, would be a real safeguard for the peace of the world. In any case that is a subject that may well be studied by those sincerely anxious to put an end to the present system of International anarchy.

Official statement as Minister of the Blockade (31 August 1917)