You must value innocent lives. However once we start doing that calculus we have to consider deaths if we do nothing versus if we act. Further our speculation about future events is just that - speculation and guess work. Clearly the administration expected more surrenders and thus fewer casualties. However they also recognize that doing nothing may result in many casualties as well - both Iraqi due to Sadaam's regime, and possible American casualties from future terrorism.

Thus applying the calculus is difficult. Further people will disagree on how it ought to be calculated.