Ashford Laboratories, Inc. (Ashford) shipped medication to Mabson Pharmaceuticals, a Nigerian importer. A letter of credit for payment for the medication was established in Ashford’s favor issued by Savannah Bank of Nigeria, Ltd. (Savannah) (defendant). The letter of credit was to be paid in New York in United States dollars (USD). For Savannah to make payment in USD, it had to receive a foreign exchange of USD for the Nigerian currency from the Central Bank of Nigeria. After the letter of credit was issued, the Nigerian government implemented a policy that had the effect of requiring Ashford to file a claim in order to receive payment under the letter of credit. Because Ashford did not file the required claim, Savannah was unable to receive an exchange of currency and did not make payment as required by the letter. Optopics Laboratories Corporation (Optopics) (plaintiff), the assignee of Ashford, sued Savannah for payment in the United States District Court for the Southern District of New York. Savannah moved for summary judgment, arguing that the act-of-state doctrine prevented a United States court from interfering with the currency-exchange policies of a foreign nation. Optopics also filed a motion for summary judgment.