Aircraft manufacturer Bombardier has requested a reopening of the U.S. tariff case relating to its C-Series passenger jet. It alleges information has emerged that shows Embraer in fact has a competing product. Boeing, the petitioner in the case, has since announced a partial merger with Embraer. Politically a reversal of the tariff decision seems untenable – aerospace accounts for 18% of the U.S. trade deficit with Canada. Bombardier may therefore need relief from either the NAFTA or WTO dispute panels. This is a material issue. Imports of all jet aircraft from Canada were $3.0 billion i...