In its bid to recast NAFTA (the North American Free Trade Agreement), the U.S. secured the buy-in of Mexico last week, but it still faces resistance from Canada, the treaty’s third partner. The U.S. doesn’t have any leverage in its discussions with Canada, and some of its proposals could end up costing consumers more, according to Wharton management professor Mauro Guillen and Fordham University adjunct law professor Matt Gold . The U.S. posture in the discussions could also erode its image as a champion of free trade, and protectionist policies would come back to haunt it, they warned. Guillen and Gold shared their views on the Knowledge at Wharton radio show, which airs on  Wharton Business Radio on SiriusXM . (Listen to the full podcast at the top of this page.) Last week, when the U.S. announced its deal with Mexico, the country braced itself for a recalcitrant Canada. The U.S. Trade Representative stated on August 31 that U.S.…