Trump reimposes Canadian aluminum import tariff to stem ‘flood’; Canada retaliates Trump reimposes Canadian aluminum import tariff to stem ‘flood’; Canada retaliates August 7, 2020 dzadmin Comments 0 Comment The decision comes more than a month after U.S. Trade Representative Robert Lighthizer expressed concern about recent struggles by American aluminum producers. Canada quickly responded with retaliatory tariffs worth $2.7 billion.