According to conventional wisdom, a strong national leader will force a weak one, or one with less popular support, to buckle in tough negotiations.

By that logic, U.S. President Donald Trump has the whip hand in trade talks with Prime Minister Shigeru Ishiba. Yet, Ishiba has held out, resisting U.S. pressure to sign a quick deal, a position that is strengthened, ironically, by Ishiba’s weakness.

The prime minister cannot afford to make concessions as the July 20 Upper House election approaches. His spine is stiffened by the failure of the U.S. to make clear its demands and the U.S. president’s record of ripping up deals that even he negotiated. Clarity and trust are the essential prerequisites of successful negotiations. Neither exists today.