I've read this, and I don't buy it. The "plan" was a standard plan that everyone knew about---like saying we have a "plan" to invade Iran. Of course we do. Conservatives need to give up the witch hunt of trying to pin Pearl Harbor on FDR and stick to his REAL crimes, which were numerous and devastating.
Beyond peradventure. But those plans are secret, and the existence of them is an open secret - we don't go around saying out loud that we have, for instance, a plan to invade Mexico or Canada. But I assume that we do.The issue raised by The New Dealers' War was not the existence of the plan but the publication of it. How did it get to the Chicago Tribune (or whatever Chicago paper it broke in)? The investigation of it petered out, nobody - including the prime suspect - paid any price for it. Was that because Roosevelt wasn't vindictive, or was it because the leak suited his purpose and was done at his behest?
We don't know who leaked it, but we do know that FDR had motive and opportunity - and that no one was punished for doing it. To say that FDR didn't do it is an unprovable negative. That doesn't make it false, just because it could never be proven true.