How Trump’s Trade War Could Hurt Republican Efforts to Hold the Senate

President Trump’s decision to escalate a trade war with Canada is threatening to hurt Republicans in the midterm elections, with several Senate battleground states on the northern border feeling an outsize impact.

Many voters say they are upset about the trade war, including some who cast ballots for Mr. Trump in 2024 with hopes that he would bring them relief from rising prices, according to more than four dozen interviews across six states at the center of the battle for control of the Senate.

The intensifying trade conflict — touching steel, dairy, appliances, automotive parts and agricultural equipment — has forced some Republicans to play defense. Democrats have highlighted the costs of the trade fight, which has spooked financial markets and threatened to accelerate inflation driven by Mr. Trump’s unpopular war with Iran.

In Maine, Senator Susan Collins, a vulnerable Republican, has pushed Mr. Trump to de-escalate the trade war. In Michigan, the Republican nominee for Senate, Mike Rogers, has appeared to stand uneasily with Mr. Trump’s trade policy.

Nationwide, 78 percent of likely midterm voters who backed Mr. Trump in 2024 still supported his trade policies, but 19 percent oppose them, according to the latest poll from The New York Times and Siena University. The poll did not ask voters specifically about the trade war with Canada.

The impact of the trade war is felt acutely in states that are along the northern border or have heavily industrial and agricultural economies that make them reliant on trade with Canada — characteristics shared by some of the most competitive Senate battlegrounds.