Earlier this week, the Trump administration announced that they have reached a handshake agreement with Mexico on NAFTA terms that include a number of demands made by the AFL-CIO last summer. Included in the deal was boosting the amount of automotive content that had to be sourced from within the NAFTA region, raising that threshold to 75% from 62.5%. This increases pressure on auto manufacturers to source their materials in North America, boosting the hiring of workers in the region. The deal also requires that 40-45% of that content comes from factories where workers earn at least $16 an hour, which is much higher than the wage in most Mexican factories. Thus, factories would have an incentive to keep workers in the U.S. and Canadian factories.
See "Trump’s Nafta Rewrite Holds Promise for Labor Unions", Josh Zumbrun, The Wall Street Journal, August 31, 2018