Republicans have been facing a problem with voters over high gasoline prices for months " but the economic pain from near-record diesel fuel prices looks set to hit at the worst possible time for them. The war in Iran, disruptions in Russian production and refining bottlenecks have sent the price of diesel fuel rising faster than that of gasoline or crude oil, and it's now grinding toward an all-time record just two months ahead of the midterms. That matters for Republicans in particular because diesel prices hit first " and hardest " in rural areas and affect blue-collar businesses like farming and trucking before spreading to suburban dinner tables and the rest of the economy.