The Trump administration’s controversial plan for new tariffs may seep into the debates of competitive House races — well beyond Pennsylvania steel country — that will determine in November which party controls the chamber.

Opponents of the tariffs on steel and aluminum also warn that if the administration carries through with the proposal and if other nations retaliate, the issue could spill into even more congressional districts, including in Republican-leaning farm country.

Fresh off the super-tight margin in Pennsylvania’s 18th District special election Tuesday, political observers in both parties say they are assessing how big a factor the tariffs could become in November. CQ found additional districts in Pennsylvania, Illinois, Ohio, Michigan, Minnesota and Iowa that could gain or lose jobs over President Donald Trump’s proposal. Districts that produce steel and aluminum could benefit, while districts where manufacturers make products out of bulk metals could face higher prices.

“Believe me, there’s a lot of reassessment going on  . . .  about what’s going on in these campaigns,” said G. Terry Madonna, director of the Center for Politics and Public Affairs at Franklin & Marshall College in Lancaster, Pa.

The Michigan Republican Party, for one, has not taken an official position on the policy, said spokeswoman Sarah Anderson.

“We play the hand that we’re dealt,” she said.

Michigan districts such as the 6th, held by GOP Rep. Fred Upton, could both gain and lose from the tariff plan, according to CQ’s analysis. The party will “look at the entire political landscape” in determining whether it will speak out on tariffs in some way, Anderson said.

Republicans for decades have backed pro-business free-trade policies and have largely opposed protectionist measures, such as the tariffs that Trump supports. But Trump’s base in the populist wing of the GOP supports such measures, as do Democratic-leaning unions like the AFL-CIO.

In Pennsylvania’s 18th District, outside Pittsburgh, both Democrat Conor Lamb and Republican Rick Saccone embraced the tariffs in theory. Trump held a rally for Saccone last weekend, but it appears that wasn’t enough to help him beat Lamb in a congressional district the president carried in 2016 by nearly 20 percentage points. Lamb led by just several hundred votes on Wednesday, while Republicans considered whether to challenge the results.

If the tariffs couldn’t hold GOP voters in the heart of steel country, then it seems unlikely they would sway voters in other districts.

Madonna believes there is no doubt that the steel tariffs helped Saccone. But he said they also helped Lamb.

“It probably helped Lamb because his support reiterated to the workers, the working-class voters that came out for him, that he was truly going to stand for their interests,” Madonna said.   

‘Very fluid situation’

The Democratic Congressional Campaign Committee on Wednesday added new incumbents to its retirement watch list because of Lamb’s apparent victory, including the seat of Rep. Erik Paulsen, R-Minn., whose district stands to lose if the tariffs take effect, according to the CQ analysis.

“A huge number of House Republicans woke up today and realized that their district is a lot more friendly to Democrats than Pennsylvania’s deep-red 18th District,” DCCC spokesman Tyler Law said Wednesday in a news release. He referenced the December tax overhaul (PL 115-97) and other issues, including “chaos and anxiety caused by the Trump administration,” but did not specifically note the tariffs, which many Democrats favor.

Political insiders say they aren’t yet sure how much tariffs will influence debate in the November midterm elections, especially if foreign retaliation for the tariffs hits consumers and business sectors.

“There is going to be the retaliation factor, and so I think that outside of some of the Rust Belt districts, there’s going to be an impact in farm country, which is obviously Trump country,” said Matt McAlvanah, who worked for the U.S. trade representative during the Obama administration and now advises Farmers for Free Trade, which opposes the tariffs.

“We’re focusing a lot of our energy on amplifying the voices of farmers who are potentially going to get hit with retaliation,” McAlvanah said. “When you start seeing 10, 20, 30 percent retaliatory tariffs coming out of the pockets of farmers, we believe that’s going to have huge political implications.”

Matt Mackowiak, who runs the Potomac Strategy Group and serves as GOP chairman in Travis County, Texas, called the matter “a very fluid situation,” given that it still isn’t clear how the White House will implement the tariffs. The issue is less likely to be a factor in Texas races, he said, than in the Midwest, where more jobs tied to manufacturing, imports, and steel and aluminum production are at stake. 

Trump has already said Canada and Mexico would be exempt, at least temporarily, and that other countries could broker their own deals with the United States.   

“Any prediction about what it’s going to mean for particular cities and counties and industries is a bit premature,” Mackowiak said. “It also depends on retaliation; we’re several steps away from knowing how this all plays out.”

Randy Leonard contributed to this report.