The legal basis of such threats against Iraq and their enactment involves an assessment of whether the UNSC can authorize them under Article 42 of the UN Charter, and whether this is incompatible with Article 2(4), which prohibits threats and the use of force. An imperfect decentralized military option has evolved for use by the USA and Britain, in particular. It is also visible in the 'safe havens' and no-fly zone created in the north of Iraq for the Kurds. But the push towards intervention has gathered momentum, and a second no-fly zone has been created in southern Iraq. Humanitarian motives have been invoked. The military activities threatened in 1998 were directed at enforcing UNSC resolution 687 of April 1991, which included provisions for the removal of weapons of mass destruction under international supervision (UNSCOM). Iraq, however, failed to comply fully with these terms. The frustration leading to threats and airstrikes was understandable - but it did not necessarily make them legal. States may seek to use force because they cannot obtain a UNSC mandate and because 687 can no longer provide one after the initial action against Iraq in 1991. All the same, there remains no clear resolution authorizing the use of force or the threat of it - however attractive a policy based on the latter might appear.
White, Nigel D. (1999) The Legality of the Threat of Force Against Iraq, Security Dialogue 30 (1): 75–86.