Greer Says Measures Could Target Imports From 60 Countries as Trump Expands Tariff Agenda. On Tuesday, U.S. Trade Representative Jamieson Greer announced that the administration of President Donald Trump is preparing a new round of tariffs on dozens of countries. Greer’s remarks come just days before the tariffs implemented by Trump on Feb. 24 are set to expire unless Congress approves an extension. The U.S. president imposed the broad-based tariff after the Supreme Court struck down the duties he had previously ordered. Those new duties will take effect in 30 days and exclude, among other products, energy, potash, critical minerals and fish.