The National Post reports in its Saturday, Aug. 4, edition that Mexican trade negotiators said Friday they will be back in Washington in a few days for a third straight week of two-way North American free-trade agreement talks with the United States. The Post's Tom Blackwellw writes that whether Canada will finally join the other countries at the table, or stay on the outside looking in, remains unclear. The meetings tentatively set for next Wednesday or Thursday will probably deal in part with a red-line issue for Canada -- the U.S. demand for a "sunset clause" that would require NAFTA to be reapproved every five years, said Mexican officials. They insisted Canada had to be involved in a final deal -- although they also said they have already resolved several NAFTA chapters alone with the U.S. An unnamed source said definitively they would not. Ildefonso Guajardo, Mexico's economy minister, said he and his colleagues talk to Canadian Foreign Affairs Minister Chrystia Freeland "every day" and that NAFTA's northernmost partner "has to" be brought back into the formal negotiations. He did not, however, suggest a timeline. Canadian officials said any notion that they have been frozen out is erroneous.