WASHINGTON ¨C Tehran stands to gain billions of dollars from a 60-day reprieve from U.S. sanctions announced on Monday, but unwinding more than four decades of restrictions poses legal, political and commercial challenges that could take years.

At issue is whether an interim U.S. deal with Iran can translate into lasting economic relief, given the complexity of dismantling a sanctions regime that spans U.S. law, international measures and private-sector risk concerns.

The United Nations, the U.S. and the European Union have imposed sanctions and trade embargoes and have frozen assets since the late 1970s over Iran¡¯s nuclear program, human rights violations and support for militant groups around the region.

Under a 14-point memorandum of understanding signed by the U.S. and Iran last week, Washington is to start abolishing all types of ?sanctions using ?a schedule to be forged in a final deal within 60 days ¡ª a period that can be extended.

On Monday, the U.S. Treasury issued a temporary general license allowing the production, delivery and sale of crude oil and petrochemical and petroleum products of Iranian origin through August 21.

Removing the remaining sanctions ¡ª if it happens ¡ª would represent a stark change in U.S. policy toward the Middle East, which has long focused on curbing Iran¡¯s influence and using financial pressure to weaken its theocratic government.

It would also be difficult, requiring executive action for some measures, approval by Congress for others and close coordination with the U.N. and other countries that have imposed their own sanctions. Companies, wary after decades of restrictions, could also blunt the impact.

¡°You have this tangled nest of sanctions, and it¡¯s not just executive orders, it¡¯s congressional sanctions,¡± said Juan Zarate, deputy national security adviser for combating terrorism under former President George W. Bush.

Washington first sanctioned Iran in 1979, after revolutionary students seized the U.S. Embassy in Tehran, holding diplomats hostage.

Since then, Congress has passed half a dozen sanctions laws and presidents have issued executive orders over Iran¡¯s nuclear program and its support for groups the U.S. deems terrorist organizations including Hamas, Hezbollah and Yemen¡¯s Houthis.

Since early 2025, the Treasury¡¯s Office of Foreign Assets Control (OFAC) has imposed sanctions on more than 1,000 people, vessels and aircraft, according to Treasury data.

Delisting thousands of entities designated for sanctions would take OFAC at least a year, said Jeremy Paner, a partner at law firm Hughes Hubbard & Reed and a former U.S. sanctions official.

U.S. President Donald Trump can rescind executive orders issued on Iran, but some measures ¡ª including sanctions on Hamas and Hezbollah ¡ª are mandated by law and will have to ?be removed or amended by Congress, where the interim deal has already sparked...