The U.S. Justice Department's antitrust division was directed earlier this week to pause all work with the Canadian government as the trade dispute between the neighboring nations intensifies, according to a report.The chief of the antitrust division's international section, Lynda Marshall, ordered officials on Wednesday to halt all cooperation on cases and engagement on policy issues with Canadian authorities, without providing a reason for the directive, according to emails obtained by The Wall Street Journal.Section chiefs in the antitrust division were also instructed in another email on F...