Loath as I am to come to Teribus' defence, there are grey areas and it is wrong to accuse a man of lying until you are in possession of all the facts.
I have refused to carry out an order because the person giving it was not in a fit state to issue such an order. For a few seconds I saw my career hanging by a gossamer thread, but fortunately there were no repercussions (very fortunately, because had I carried out the order it would have terminated the career of an unfortunate subordinate). The event was glossed over and the fool who gave the order later went on to retire with the plaudits of many ringing in his ears.
The key phrase is 'believe to be illegal'. On that pin, many angels dance. I honestly do not know how I would have reacted had I still been in a position to be sent to Iraq. I did not believe in the legality of the war, but I don't know if I would have had the balls to make a stand.