Every night, thousands of fervent, flag-waving supporters of Iran’s Islamic Republic take to the streets to vent vitriolic rage at their American and Israeli attackers. They celebrate surviving 40 days of war, a fragile ceasefire, and now negotiations in which they believe Iran has the upper hand. The chants also herald another change: The ascendance of a new hard-line cadre of the Islamic Revolutionary Guard Corps, which has stepped up as the United States and Israel have assassinated scores of senior military and political figures, including the longtime supreme leader, Ayatollah Ali Khamenei. Why We Wrote This After the U.S.-Israeli war’s “decapitation” strikes against top Islamic Republic political and military leaders, who is this new generation that has taken the reins in Iran? They are more hard-line than their predecessors, and less willing to compromise. U.S.…