Washington is trying to turn economic pressure into a decisive weapon against Iran, but its campaign is running into a formidable obstacle: China’s refusal to let the United States dictate its trade relationships.

The Trump administration says new sanctions will sever the financial networks sustaining Tehran. Treasury Secretary Scott Bessent described the effort as an “economic onslaught” designed to cut “every economic lifeline” to Iran, while warning that entities handling Iranian funds could be expelled from the dollar system.¹ The approach is intended to force countries to choose between access to U.S. markets and continued commerce with Tehran.

Beijing, however, rejects that choice. China is Iran’s largest oil customer, with independent Chinese refineries buying discounted crude through opaque shipping and payment networks. Although U.S. pressure has reduced imports—from roughly 1.57 million barrels a day in February to 534,000 in August—previous sanctions have done little to halt the broader flow.²

Chinese officials cast the dispute as a matter of sovereignty and legality, not sanctions compliance. Foreign Ministry spokesperson Lin Jian said cooperation with Iran “has always been conducted within the framework of international law” and should not be “interfered with or disrupted.”³ Beijing has also threatened “all necessary measures” to protect its interests, raising the prospect of retaliation against U.S. financial institutions or exports of critical minerals.

The two sides therefore agree on one point—that the sanctions are consequential—but draw opposite conclusions. Washington sees economic isolation as a substitute for military escalation and a path to Iranian capitulation. China and Iran describe it as coercion, insisting that pressure will provoke resistance rather than surrender. U.S. caution is already visible: Washington avoided sanctioning major Chinese banks, with Bessent asking, “Why would I want to blow up the global financial system?”³ The result is a campaign that may squeeze Iran while simultaneously widening the confrontation it was meant to contain.