You seem to not understand the role of Secretary of State. His JOB is maintaining diplomacy and keeping communication open with the other side until the minute the president decides diplomacy will not work anymore. Powell is the "good cop"... the one that can still get a seat at any table. We need a "good cop" and a "bad cop" in international relations... and Dubya has both in Powell and Rumsfeld.
Powell is performing the job that has been given to him, with the full blessing of the president. How many times does Bush have to say that?