In August, President Donald Trump ordered a temporary suspension of tariffs on as much as 300,000 metric tons of imported beef, including lean trimmings intended for ground beef. The administration said imports would be sold below market prices to help consumers.

Scott Birker, a cattle producer near Garrison, Iowa, said the announcement hit producers hard because it came amid an already volatile market and limited U.S. cattle supplies. Birker runs a herd of about 150 cows and is a regional vice president of the Iowa Cattlemen’s Association.

The supply constraints have built over time. Drought across much of the West has raised hay costs and contributed to a smaller national herd, now at a 75-year low, according to Iowa State University livestock economist Zach Raff. Ground beef has been selling for about $6.80 a pound.

The tariff change contributed to a decline in cattle prices, but uncertainty about future import policy may pose a longer-term problem, Raff said. Producers weighing whether to keep young female cattle for breeding could hesitate if they fear imports will expand and domestic prices will fall. That could slow efforts to rebuild the herd and eventually increase supplies.

The import allowance amounts to roughly 2% of U.S. beef consumption. Average ground beef prices in September were only about 13 cents per pound below August’s average, a modest decrease that has done little to ease the squeeze on shoppers.

The policy is becoming a point of contention in Iowa’s U.S. Senate race. Republican Rep. Ashley Hinson, a candidate for the state’s open Senate seat, has criticized the import move, saying affordability matters but the policy is not the right way to achieve it. She has argued for helping cattle producers expand their herds.

Her Democratic opponent, state legislator Josh Turek, has criticized Hinson’s support for other Trump trade policies, arguing that farmers depend heavily on access to markets and trade. In the governor’s race, Democratic state auditor Rob Sand has also attacked Trump’s trade policies, while Republican businessman Zach Lahn has not taken the same approach.

Iowa Republican strategist David Oman said the beef issue could matter in close contests, where a small number of voters may decide the outcome. The political stakes extend beyond Iowa: Texas, Nebraska, Montana and Kansas are also major beef-producing states with competitive races.

Some producers remain supportive of Trump despite their concerns. Birker said he intends to vote Republican and continues to approve of the president, describing the policy challenges as a long-term process. Seth Watkins, a cattle producer near Clarinda and a Democrat, said the trade decisions have left him frustrated with both Trump and Congress, which he believes should exercise stronger oversight.

Agriculture Secretary Brooke Rollins defended the temporary tariff change at Iowa’s Farm Progress Show, acknowledging it might not be popular with producers while arguing that the administration was willing to make difficult decisions. Trump was scheduled to visit Sioux City later that week as part of his midterm campaign push.