At a Cuban port in June 2013, the Chong Chon Gang took on secret cargo: some 240 tons of Soviet-era weapons.

Later, under the direction of diplomatic staff stationed in Cuba, the ship’s crew of 32 North Koreans layered thousands of bags of raw sugar over the weapons, concealing them from sight.

Many of the crew were employees of the state, according to a 2016 United Nations report, with salaries paid by a marine ministry in Pyongyang. They were tasked with smuggling home the load of arms by piloting the nearly 40-year-old merchant ship through the Panama Canal, where the ship’s officers had been instructed to declare only the sugar.

Acting on guidance from US officials, Panamanian authorities raided the ship as it waited at the canal’s mouth, arresting the crew and touching off multiple minor diplomatic crises.

… “A nuclear weapons capability has to be viewed from a complete system perspective,” explains Graham Ong-Webb, research fellow at the S. Rajaratnam School of International Studies in Singapore. “In order to have a full-fledged capability, you have to have real system to protect assets.”

Dr. Ong-Webb served as an expert witness in a 2015 case stemming from the ship’s interdiction. In that case, Singapore-based Chinpo Shipping Company, Ltd. was fined $180,000 for transferring tens of thousands of dollars on behalf of the Chong Chon Gang’s North Korean operator.