~61- fear that onets country might suddenly be attacked in the midst of apparently profound peace has often been voiced, but, at least in the last century and a half, it has never been realized, As advancing technology makes war more horrible, it also makes the decision to resort to it more dependent on an elaborate psychological preparation, In international politics today few things are more certain than that an attack must have an antecedent dispute of obviously grave character, Even those statesmen who remain blind to the most blatant warnings will understand the significance of those warnings once the attack oceurs,°© Especially today, when there are onl: tio or three powers of the first rank, the identity of the major rival is unambiguous, In fact, as Professor Jacob Viner has pointed out, it is the lack of ambiguity concerning.the major rival which makes the bi-polar power system so dangerous. a a There is happily little disposition to neLioveatsieatomic bomb by its mere existence and by the horror implicit in it "makes war impossible," In the sense that war is something not to be endured if any reasonable alternative remains, it has long been "impossible." But for that very reason we cannot hope that the bomb makes war impossible in the narrower sense of the word, Even without it the conditions of modern war should have been a sufficient deterrent but proved not to be such, If the atomic bomb can be used without fear of substantial retaliation in kind, it vill Clearly encourage aggression, So much the more reason, therefore, to take all possible steps to assure that multilateral possession of the bomb, should that prove inevitable, be attended by arrangements to make as nearly certain as possible that the aggressor who uses the bomb will 26. It is possible, of course, that a state which has resolved to fight as a result of a political crisis may for tactical reasons await the partical Cissipation of the crisis tension, perhaps furthering the process by a deceptive acquiescence or surrender; but oven if this were likely—-which it is not-—-the identity of the attacker would still be Inowm, fu