The Trump administration on Friday said it had granted tariff exemptions on some Canadian imports, an implicit acknowledgement that President Donald Trump’s signature trade policy could be hurting Republican candidates running in the Nov. 3 midterm election.

The canceled tariffs include 50% duties on some agricultural items. These duties were applied to Canadian products after the country withdrew from trade negotiations with the Trump administration in late August.

Polls show Democrats have a solid chance to win majorities in both the House and Senate.

Republican Sen.…