The U.S. average diesel price reached an all-time high of $6.5107 per gallon on Sept. 21, 2026, according to AAA, increasing costs for farmers, logistics companies and independent truckers during harvest season. Farm fuel expenses rose $11 per corn acre and $7 per soybean acre year over year, while economist Steve Hanke said record diesel prices were turning farmers and truckers against Trump. The rally followed disruptions linked to the U.S.-Iran conflict, Ukrainian attacks on Russian refineries, weekend meetings in Muscat between U.S. officials and Houthi representatives, reduced Strait of Hormuz traffic and damage to the East-West Pipeline to Yanbu. Former President Donald Trump called higher gasoline prices an "inexpensive price to pay," although the records also identify him as President Donald Trump and available data do not establish a broad political shift among farmers or truckers. Supply constraints lifted Brent crude to $101.60 per barrel and WTI to $93.04, while threatening higher agricultural-input prices, inflation and diesel-driven trucking bankruptcies.