The United States, along with France, Germany, Britain, China and Russia, reached a historic deal with Iran last July that lifts most sanctions in return for curbs on Iran’s nuclear program. The deal, codified in the Joint Comprehensive Plan of Action and endorsed by the United Nations Security Council Resolution 2231, specifically includes allowing non-American banks to operate in Iran.
“Obama Needs to Protect the Iran Deal,” Seyed Hossein Mousavian and Reza Nasri, The New York Times, June 20, 2016.