The expansion of American sanctions is testing both Iran’s resilience and the willingness of its trade partners to resist U.S. financial influence. Since 1979, U.S. sanctions against Iran have evolved from commercial restrictions to a global financial mechanism that pressures foreign companies to choose between trading with Iran and accessing the American market. The latest phase, known as Operation Epic Fury, has taken this strategy further by implementing direct sanctions, secondary sanctions, and targeting oil, maritime transport, finance, and networks that help Iran circumvent restrictions. This new approach aims to push countries that trade with Iran to cut ties or risk losing access to the U.S.-dominated financial system. The evolution of these sanctions began with the 1979 hostage crisis and has since grown into a complex system that limits Iran's access to global markets. The Iranian nuclear program brought international pressure, leading to UN sanctions from 2006 to 2010. These eventually contributed to the 2015 Joint Comprehensive Plan of Action (JCPOA), which eased many sanctions in exchange for Iran limiting its nuclear activities. However, the Trump administration withdrew from the deal in 2018, viewing it as insufficient to address Iran’s ballistic missile program or its support for regional groups. Since then, the U.S. has gradually restored sanctions, intensifying its economic pressure on Iran and its allies. Operation Epic Fury, launched in February 2026, combines military, maritime, and economic measures. Recent statements from President Donald Trump and Treasury Secretary Scott Bessent indicate a focus on an "economic assault" against Iran. This strategy targets third countries that continue trading with Iran, aiming to cut off access to the dollar-based financial system. The scope of sanctions now includes oil, maritime transport, aviation, technology, cryptocurrencies, and supply chains. The challenge lies not in the number of sanctioned entities, but in the ability of the Treasury to target the financial infrastructure that connects Iran to global markets. China is Iran’s primary trade partner, receiving about 92% of its oil exports, which are often re-labeled and paid for in local currency to avoid U.S. sanctions. This system allows Iran to maintain a financial lifeline while minimizing the exposure of Chinese banks to penalties. The U.S. has so far focused on smaller Chinese entities, avoiding actions that could disrupt the global economy. Meanwhile, other countries like the UAE have reduced trade with Iran to limit their exposure to sanctions, and Turkey, Pakistan, and Iraq remain economically linked to Iran despite growing U.S. pressure. These nations face potential trade disruptions if sanctions are tightened further. The outcome of this economic battle will depend on the resolve of Iran’s trade partners and the U.S. ability to extend its financial influence beyond Iran’s borders.