Republican Sen. Jerry Moran of Kansas raised dire concerns over the Trump administration’s intensifying tariff war with China, warning Department of Agriculture Secretary Sonny Perdue on Monday that the impact on American farmers could prove devastating.

In a letter to Perdue, the lawmaker contended that the back-and-forth levying of tariffs threatens “to cause long term damage to U.S. agriculture.”

“Kansas farmers and ranchers understand the need to hold China accountable for bad behavior on trade,” he wrote. “Yet, net farm income has fallen by 50% since 2013 and the trade war has pushed commodity prices down even further. Many farmers and ranchers are on the verge of financial collapse.”

Earlier this month, trade negotiations between the U.S. and China collapsed, prompting tensions to escalate further following more than a year of tit-for-tat tariffs.

Less than two weeks ago, the U.S. hit $200 billion worth of Chinese goods with tariffs ranging from 25% to 10%. China retaliated days later with plans to slap new tariffs of between 25% to 5% on about $60 billion of U.S. products.

Though President Donald Trump has falsely claimed that the tariffs he’s imposed are being paid by the Chinese themselves, White House chief economic adviser Larry Kudlow acknowledged last week that American consumers and businesses will have to foot the bill.

On Wednesday, Purdue announced that an estimated $20 billion in trade assistance would be given to farmers to help ease their strain, similar to last year’s $12 billion in relief. But Moran argued that isn’t a sustainable solution, noting that producers have been told not to expect further payouts.

“This inherent unpredictability of ad hoc disaster assistance underlies the strong preference of farmers and ranchers for markets to sell their livestock and crops instead of government payments,” he said.

Throughout Trump’s tenure, Moran has voted in line with the president’s positions roughly 88% of the time, according to FiveThirtyEight.com. Although high, the figure falls on the lower end of the spectrum among his fellow Republicans in the Senate.

In March, the lawmaker supported overturning Trump’s national emergency declaration made by the president in an effort to obtain funding for a southern border wall. Detailing his stance in a Twitter thread, Moran agreed with Trump’s concerns over border security, but said that the declaration had violated the Constitution and was unnecessary.