The National Post reports in its Thursday edition that trade watchers are shocked by the Trump administration's latest tactic to strengthen its tariff wall against Canada following a legal setback. The Post's Tracy Moran writes that last week the office of the U.S. Trade Representative launched investigations into 60 economies under Section 301(b) of the Trade Act to assess whether they have failed to ban imports made with forced labour. Critics claim these probes are merely a "show trial" with a predetermined outcome against trading partners like Canada. Canada and Mexico are being grouped together with China and dozens of other countries for these investigations. The inclusion of Canada "was unbelievably shocking to me," said Cato Institute's Clark Packard. "This poisons the well in terms of any USMCA negotiation," Mr. Packard added, referring to the renegotiation of the U.S.-Mexico-Canada trade agreement scheduled for July. Section 301 enables the U.S. trade representative to unilaterally restrict imports or suspend trade agreements over unjustifiable, unreasonable or discriminatory trade practices that burden domestic commerce. Investigations under the section can take a year, but officials are speeding the process.