Primary vs. Secondary Sanctions
To understand the global reach of US policy, it’s crucial to distinguish between two types of sanctions. Primary sanctions are straightforward: they prohibit US citizens, residents, and companies from doing business with a targeted country or entity,
like Iran. These rules apply to anyone on US soil or transactions that pass through the US financial system. Secondary sanctions, however, are what truly project American economic power globally. They target non-US individuals and companies for engaging in specific business activities with a sanctioned country. Essentially, the US government tells the rest of the world: if you do significant business with sanctioned parts of Iran's economy, you risk being cut off from the US market and its entire financial system.
The Power of the US Dollar
The effectiveness of secondary sanctions hinges on one critical fact: the dominance of the US dollar and the central role of the American financial system in global trade. Most international transactions, especially for major commodities like oil, are conducted in US dollars. This gives the US Treasury immense leverage. For a foreign bank or multinational corporation, losing access to US correspondent banking relationships is a corporate death sentence. It means being unable to process dollar-based payments, effectively crippling their ability to conduct international business. This powerful threat forces many foreign firms in Europe and Asia to abandon otherwise legal and profitable business in Iran, rather than risk exclusion from the far larger and more critical US market.
Targeting Iran's Economic Lifelines
Over the years, the US has applied secondary sanctions to strangle key sectors of the Iranian economy. The primary targets have been Iran's energy and financial sectors, which are the main sources of revenue for the government. Sanctions have aimed to drastically reduce Iran's oil exports by penalizing foreign buyers, refiners, and shipping companies. Similar restrictions have been placed on Iran's central bank and other financial institutions, making it incredibly difficult for the country to receive payment for its exports or finance imports. The sanctions extend to other industries as well, including shipping, shipbuilding, automotive, and trade in precious metals, creating a comprehensive and suffocating economic environment.
A Global Dilemma for Companies and Countries
Secondary sanctions create a significant diplomatic and commercial dilemma for third countries, including major economies like India and China. These nations may not agree with US policy towards Iran and may have their own strategic and economic interests in maintaining ties with Tehran. Historically, India has relied on Iranian oil and has invested in strategic projects like the Chabahar Port. However, the threat of being locked out of the US financial system often forces governments and companies in these countries to comply with US sanctions, even if reluctantly. This extraterritorial reach is controversial, with some critics arguing it infringes on the sovereignty of other nations by forcing them to adopt US foreign policy objectives. Despite this, the fear of losing access to the US market remains a powerful motivator. For instance, following the US withdrawal from the JCPOA nuclear deal in 2018, many European companies that had rushed back into Iran quickly pulled out again.
Recent Developments and Future Outlook
The landscape of Iran sanctions remains fluid, particularly following the 2026 US-Iran conflict and subsequent diplomatic negotiations. In recent days, the US has threatened to expand secondary sanctions to compel countries to sever remaining economic ties with Iran. On August 24, 2026, the US Treasury announced 'Operation Economic Outcast,' a warning to Iran's trading partners that they must wind down their activities or face retaliation. The sectors targeted include digital assets, technology, gold, aviation, and shipping. China, Iran's largest oil customer, has publicly stated its opposition to such unilateral measures. The evolving situation underscores the central role of secondary sanctions as a tool of economic coercion, even as diplomatic paths are explored. The recent US-Iran memorandum of understanding, signed in June 2026, called for a ceasefire and included a temporary waiver on sanctions for Iranian oil exports, showing that these tools can be dialed up or down depending on the geopolitical climate.
