The outpouring of literature on pre-emptive self-defence both in advance and in the wake of the 2003 U.S. invasion of Iraq, as well as remarks by UN Secretary-General Kofi Annan in the Fall of 2004 characterizing the invasion as violative of prevailing international legal standards, suggests the continuing importance of considering aspects of pre-emption which have received little attention. In this connection, it is argued that the relevant formulation of the customary legal standard can be seen as aiming at minimizing the likelihood of defensive force being employed by mistake. The implication would thus be that clarity regarding a future threat of attack, not the imminence of the attack itself, affects whether advance defensive action is to be considered justified. Further, it is also argued that, unless one is content to simply stand on legal principle in the abstract, the importance of a threatening State's intention and capacity to attack require detailed examination and a high level of proof before considering putative defensive action to be legitimate. Finally, given the customary international legal standard's requirement that forceful pre-emptive action be taken only when no other means exist to address a threat of attack, a variety of considerations, ranging from access to non-forceful alternatives, to the viability of alternatives that exist and are accessible, demand attention prior to determining that an immediate resort to defensive force should be evaluated as permissible.