His resignation takes effect at the end of the month.
Gates said Fallon took the decision because of recent statements attributed to him that Fallon felt had created a misperception about his goals and those of President Bush.
. . .
Fallon was the subject of an article published last week in Esquire magazine that portrayed him as opposed to Bush’s Iran policy. It described Fallon as a lone voice against taking military action to stop the Iranian nuclear program.
The article is here.
Myself, I doubt at this point that Bush would start a new war. If he did, it would spell the certain doom of McCain's campaign- and possibly turn Democrats to impeaching Bush (as they should have done long ago).
But McCain is the one who sang, "Bomb bomb bomb, bomb Iran." Be warned.