A:The U.S. attack on Iraq implies two ethical (or moral) considerations. On the one hand one can argue that any unprovoked ( of course this is open to question) on another country is an immoral step. On the other hand one can posit that enforcing the clauses of a peace treaty and the suspicions of nuclear armament are a cause for invasion.
What you can gain from these positions is that "ethical considerations" are always debatable as is most of human conduct.