It didn't matter how one interpreted it. The blatant fact that you're missing is that only the UNSC had a right to interpret the resolution as it saw fit, and only the UNSC had the right to authorize use of force, which it did not do. The US did not have any legal authority to authorize use of force, only UNSC did.
""The second version of the argument that prior Security Council resolutions
authorize force centers on the “material breach” argument. This argument
apparently originated in the UK, but US officials have also mentioned it in
recent months. Blair government officials argue that the ceasefire resolution
and subsequent resolutions are like any other international agreement. In the
case of material breach of a multilateral treaty, in some cases, all the
parties may respond, including, where appropriate, by coercive
countermeasures[9].
This is indeed a curious argument. Its main concept "material breach" has made
its way into Resolution 1441[10]. The problem is that "material breach" never
was a viable basis for using force against Iraq. Security Council resolutions
are not like treaties or other agreements reached through negotiations aimed at
achieving consensus. Rather, Security Council resolutions are mandates upon
parties and must be respected with or without their consent[11]. They are
enforced, modified, or terminated by the Security Council, not by states in
general. Neither the explicit terms of the UN Charter nor the practice of the
Security Council supports any other interpretation. Under the UN Charter,
states may only use force in individual or collective self-defense in the face
of an armed attack or with the authorization of the Security Council when the
Council finds a threat or breach of international peace[12]. Thus, without
Security Council authorization, states do not have the right to use force to
enforce the Council's resolutions, whether a breach is material or immaterial.
The Security Council's history with respect to its resolutions on Iraq make
clear that it has not relinquished to the US the right to enforce its
resolutions unilaterally...
...But then it will be for the Security Council to decide the consequences.
Under the international law governing enforcement, all coercive measures are
limited by the principles of necessity and proportionality, including those
mandated by the Security Council itself[14]. Consequences should be
commensurate with the nature of the breach. To this extent the "materiality" of
the breach is not as important as finding a remedy that fits the wrong. It will
be for Security Council members to calibrate response to any failure to comply.
Thus, if the inspectors report even minor obstruction by Iraq, the Security
Council should not necessarily authorize major military force."
JURIST - O'Connell: UN Resolution 1441 - Compelling Saddam, Restraining Bush
