158 states. Factual as the criterion may be, it remains necessary to determine whether there is an armed conflict between states. This question is not a generalised one as to whether an armed conflict has become "internationalised" in any broad sense of the term ; nor is it to be determined by reference to criteria of unmanageable plasticity. The question is a precise one as to whether there is an "armed conflict ... between two or more of the High Contracting Parties ..." to the Fourth Geneva Convention. Barring a "declared war" between them, it is only if there is such a conflict that the Convention applies . But whether or not there is such a conflict turns,ex hypothesi, on whether one state is using force against the other. A demonstrable link test has to result in showing whether or not force was being used by a state. If the test premises that it is not necessary to prove that a state was using force, it is not persuasive. 27. More pertinently, if the proposed test is meant to show whether or not force was being used by a state through a foreign army, it has to have the effect of connecting the state with the use of force by the foreign army; and I do not see how it can do this unless it has a degree of specificity commensurate with the gravity of a finding that one state was using force against another and with the serious implications of such a finding for individual criminal responsibility, for, if the Convention applies, the individual becomes liable to conviction for certain serious crimes to which he would not otherwise be exposed. If the test has the requisite degree of specificity,I do not see the advantage which it possesses over the other tests concerned. Whatever may be said about the latter, they appear to have that quality. Thus, the proposed test is either unnecessary or inadequate. 7. The Test of Appellate Intervention 28. The Appeals Chamber is intervening in this part of the case because it holds that the Trial Chamber applied the wrong legal criterion. In another part of the case (and, in a sense, in this part also), the question of evaluation of facts is concerned. It may be convenient to say a word on the basis on which, I believe, the Appeals Chamber acts. 29. Assessment of facts is primarily a matter for the Trial Chamber. But appeals to the Appeals Chamber are by way of rehearing, though not involving a hearing de novo 3 J.S.Pictet, Humanitarian Law and the Protection of War Victims (Leyden, 1975), p. 50.