Time is running out for President Trump to seal the new and improved trade deal he wants with Canada and Mexico.

Successful talks with U.S. neighbors to the north and south are only half the battle; the next step is winning approval for a revised North American Free Trade Agreement from Congress, which would grow infinitely more difficult if Democrats take control of the House in November’s midterm elections, said Michael Camunez, the head of advisory firm Monarch Global Strategies and a former official in the Obama-era Commerce Department.