What was the purpose of the American diplomatic offensive against Japan?
Short answerIt aimed to make Japan withdraw from China and cease threatening American interests in the Far East.
NotesThe answer summarizes the diplomatic objective as forcing Japan to withdraw from China and stop threatening American interests in East Asia. Washington therefore wanted a major reversal of Japanese policy, not a token concession. That goal helps explain why sanctions were intended to compel submission rather than merely signal displeasure. It also clarifies why Japanese leaders could perceive the pressure as an attempt to reduce Japan to a dependent, second-rank regional position.