Jimmy Tosh’s sprawling hog farm in rural Tennessee is an unlikely battleground in the fight for control of the U.S. Senate. Yet his 15,000 acres two hours west of Nashville showcase the practical risks of President Donald Trump’s trade policies and the political threat to red-state Republican Senate candidates such as Tennessee’s Marsha Blackburn.

Tosh, a third-generation farmer who almost always votes Republican, said he’s voting this fall for Blackburn’s Democratic opponent, former Governor Phil Bredesen, in part because Trump’s trade wars are hurting his family business — a sizable one with some 400 employees and 30,000 pigs. The cost of steel needed for new barns is up, Tosh said, and the expanding pork market stands to suffer under new tariffs.

Similar concerns are roiling high-profile Senate contests in Missouri, Indiana, Pennsylvania and North Dakota, and forcing GOP candidates to answer for the trade policies of a Republican president they have backed on almost every other major issue.

In 2016, populist attacks against free trade defined Trump’s political rise. Now, as he sparks an international trade war four months before the midterm elections, few policies could be more problematic for Trump’s allies in pivotal Senate contests.

The Trump administration imposed a 25 percent tax on $34 billion worth of Chinese imports on Friday, and China is retaliating with taxes on an equal amount of U.S. products, including soybeans, electric cars and pork. The administration has penalized steel and aluminum imports from allies such as Canada and Mexico, leading to retaliation against American-made products such as blue jeans, motorcycles and whiskey.

The tension has reshaped the race to replace retiring Senator Bob Corker. Blackburn, an eight-term congresswoman, has been one of the president’s biggest boosters for the past two years, yet with the business community up in arms, she’s dramatically softened her support for Trump’s trade policies, at least.

Still, Blackburn opposed a proposal by Corker that would have given Congress new authority to check the president’s trade moves. She called Corker’s approach “a little bit too broad.”

Instead, Blackburn helped write a letter urging Trump’s commerce secretary to reconsider broad tariffs so as to avoid harm to Tennessee’s economy.

An estimated $1.4 billion in Tennessee exports are threatened by Trump’s trade moves, according to the U.S. Chamber of Commerce, a longtime Republican ally. Those exports are linked to more than 850,000 jobs in the state related to farming, steel, baked goods, car manufacturing, whiskey and more.

Nationwide, the U.S. Chamber reported $75 billion in U.S. exports will soon be subject to retaliatory tariffs. Many of the hardest-hit states are those that backed Trump and feature top-tier Senate races in November.

Indiana, where Republican Senate candidate Mike Braun is trying to defeat Democratic Senator Joe Donnelly, has more than 812,000 jobs tied to global trade, the Chamber found. In April, Braun said concerns about the tariffs were being “overdramatized.”

Missouri Senator Claire McCaskill, a Democrat, has pounded her Republican opponent, Josh Hawley, for backing Trump’s trade decisions. Hawley, whose state has more than 826,000 jobs tied to global trade, says the president is right to shake up trade deals and should have time to negotiate.

And in North Dakota, Democratic Senator Heidi Heitkamp has seized on Republican challenger Kevin Cramer’s description of the tariff fallout as “hysteria.” Cramer blames China for the trade dispute that could affect as many as 111,000 jobs.

But back in Tennessee, Blackburn has been backed into a corner by the state’s business leaders.

Tennessee whiskey maker Jack Daniel’s, for example, sends roughly 60 percent of its business out of the country. Jack Daniel’s parent company was forced to increase prices across Europe as a result of tariffs imposed by the European Union in response to Trump’s tariffs on U.S. steel and aluminum. Shares of the company dropped sharply last month after Mexico announced plans to impose a 25 percent tariff on whiskey in response to Trump’s moves.

Another major Tennessee employer, home-appliance maker Electrolux, continues to delay a $250 million expansion in Tennessee, “given the uncertainty of U.S. trade policy,” said company spokeswoman Eloise Hale.

The Democrat in the Senate race, former governor Bredesen, has seized on the issue. Even in a state Trump won by 26 points, he’s betting he can use Blackburn’s loyalty to the president against her because of the tariff-related fallout.

Blackburn is eager to change the subject. She’s quick to highlight her support for the GOP’s tax cuts. And with a sudden Supreme Court vacancy that gives the GOP an opportunity to cement a conservative majority for a generation, she’s emphasizing the importance of having a Republican Senate majority to approve Trump’s judicial appointments.