The biggest casualty of the U.S.-Iran deal may not be Israel’s Iran strategy, but the political brand Benjamin Netanyahu spent decades building as the Israeli leader who could uniquely bend Washington to his will on Iran, analysts, former U.S. officials and diplomats say.

Netanyahu shaped his political identity on an audacious assertion: that he alone could keep the U.S. and Israel in strategic lockstep on Iran. Cultivating Republican support, he cast himself as the only Israeli leader capable of influencing successive U.S. presidents and insisted that only sustained military pressure could contain Tehran.

At the height of his power, he was described by diplomats as the “American whisperer” — the Israeli leader who could pick up the ​phone and ensure Washington’s strategic calculus aligned with that of Israel. No other Israeli prime minister, they note, addressed Congress as often or built such enduring political capital across the American political system.