Abstract:
International law is considered to be fully developed on the concept of use of force and
self-defence by States. Sources of international law, namely customary international law,
conventional law, judicial pronouncements, as well as state practice, have dealt with this
issue extensively. One of the probable reasons for such a level of development is that
the need for States to be able to defend themselves or to defend their territorial integrity
and political independence is considered to be one of the cornerstones of the existence
of a State. A State that does not have the ability to defend itself might as well cease to
exist. Some of the sources of international law have, however, developed more than
others on the concept of the use of force. The question of whether the same principle of
international law can be governed by both customary and conventional international law
has since been settled by the International Court of Justice (ICJ) by concluding that
customary international principles can exist alongside treaty law. Whilst this is the case,
one may argue, albeit indirectly, that, to avoid inconsistencies, it may be prudent to leave
certain aspects of international law, e.g. use of force and self-defence, to be governed by
one source of international law. This paper, however, does not dwell much on the
inconsistencies between the principle of self-defence formulated by the United Nations
(UN) Charter and that formulated by customary law, e.g. the fact that customary
international law recognises the right for a State to defend itself against an imminent
attack, and the UN Charter is considered not to afford such a right. The interpretation
(and as we will see in the paper; it seems the ICJ also has its own interpretation) of what
constitutes an armed attack differs from State to State. Despite these differences,
however, one principle that States seem to have reached consensus on is that,
whenever the right to self-defence is invoked, any action taken in that regard should be
proportionate to the attack directed against the defending State.
