China has pushed back strongly against Washington’s threat to impose the “toughest sanctions in history” on Iran. Beijing says it opposes unilateral sanctions that lack a basis in international law or a mandate from the UN Security Council—and insists that pressure and military action will only escalate tensions. China remains one of Iran’s most important economic partners and a major buyer of Iranian crude. The standoff now raises major questions: Will Washington’s sanctions campaign isolate Tehran—or deepen the China-Iran partnership and widen geopolitical divisions across the Middle East and Asia?