The implementation of duties on steel and aluminum following the section 232 “national security” review of U.S. imports does not appear to have had a significant effect on trade flows yet. Duties were applied on March 29, yet seaborne imports of the products covered climbed 10% higher in April vs. March after a 7% rise in all imports in March vs. February. That can be seen most clearly in aluminum, where imports climbed to their highest since at least 2009 in both March and April. Concerns about which countries will be permanently exempted from the duties likely drove the March / April s...