Atrocities committed by Japan in China were very much a concern in the US (and even in Germany for that matter!) already before the war, and were incontrovertib

Atrocities committed by Japan in China were very much a concern in the US (and even in Germany for that matter!) already before the war, and were incontrovertibly the reason for the US foreign policy towards Japan then, and thus arguably a distant cause for Pearl Harbor. You'd have to argue that the US had forgotten about it, and then not gotten the memo on the atrocities committed since then.