The WTO has cleared South Korea’s appeal against American tariffs on Korea’s exports of oil country tubular goods (OCTG). It could now apply for trade sanctions against the tariffs. That relates to a case from 2014 that the U.S. took further action on in 2017. The application of sanctions would greatly complicate the recently started KORUS talks.Imports of OCTG climbed 59% in the fourth quarter on a year earlier, reaching the highest in October since May 2012. That’s been led by a 181% rise in shipments from Mexico, partly in response to increased American oil and gas production. Imports...