Because he lacks the moral fiber to fulfill a commitment he made. Illegal? Hardly!

The war is clearly illegal. It is a clear violation of international law and, as such, is also against the laws of our own country. (The last several presidents have all violated those laws with the support of congress, unfortunately.)

It is an interesting question, however. to what extent contituent parts of that war constitute illegal actions on the part of someone of low rank carrying them out. It would have been interesting if the Watada case had been argued to the finish on those grounds, but it wasn't, unfortunately.

As for the "moral fiber to fulfill a commitment" - What about the president's commitment to uphold the constitution? And what if this soldier's commitment was to uphold the constitution and defend the country? This war does neither.

There is small-group loyalty within his unit and a certain commitment that goes with that. I can understand some resentment on that level.