神戸大学法学部 国際法概論 ２００１年度 ２００１年６月１９日
助教授 濵本 正太郎
試験問題例 １２
今回は、問題が英文ですので締切を次々回講義（６月２６日）とします。
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講義で説明したように、国際司法裁判所のニカラグア事件判決（１９８６年）は慣習国際法の成立過程に関して注目すべき判断を下した。判決文の該当箇所は次のとおり。なお、引用文中の”the
rules in question”とは干渉禁止規則と武力行使禁止規則である。
出典 I.C.J. Reports 1986, p.
98, para. 186. （参考 判例集 p.
501）
It
is not to be expected that in the practice of States the application of the
rules in question should have been perfect, in the sense that States should
have refrained, with complete consistency, from the use of force or from
intervention in each other’s internal affairs. The Court does not consider that, for a rule to be
established as customary, the corresponding practice must be in absolutely
rigorous conformity with the rule.
In order to deduce the existence of customary rules, the Court deems it
sufficient that the conduct of States should, in general, be consistent with
such rules, and that instances of State conduct inconsistent with a given rule
should generally have been treated as breaches of that rule, not as indications
of the recognition of a new rule.
If a State acts in a way prima facie incompatible with a recognized rule,
but defends its conduct by appealing to exceptions or justifications contained
within the rule itself, then whether or not the State’s conduct is in fact
justifiable on that basis, the significance of that attitude is to confirm
rather than to weaken the rule.
慣習法成立過程の代表的先例である北海大陸棚事件判決では、いわゆる「二要素」につき次のような判示がある。
出典 I.C.J. Reports 1969, p.
43, para. 74. （参考 判例集p.
160）
Although the passage of only a short period of time is not necessarily,
or of itself, a bar to the formation of a new rule of customary international law
on the basis of what was originally a purely conventional rule, an
indispensable requirement would be that within the period in question, short
though it might be, State practice, including that of States whose interests
are specially affected, should have been both extensive and virtually uniform…
and should moreover have occurred in such a way as to show a general
recognition that a rule of law or legal obligation is involved.
この二つの判示は、一見矛盾するように見えるものの、整合的に理解することも可能である。
問１ 矛盾する可能性のある点を指摘せよ。
問２ どのように理解すれば両判決を整合的に把握できるか。