U.S. consumer inflation jumped more than expected in September, government data showed Wednesday, as the ongoing U.S. war with Iran continued to push energy costs higher, deepening strains on American households ahead of next month’s crucial midterm elections. The uptick underscores intensifying voter worries over the high cost of living and arrives precisely as President Donald Trump travels across key U.S. states to shore up support for his Republican party as it strives to retain control of Congress in the face of mounting political headwinds.
The consumer price index (CPI) rose 3.7% year-over-year in September, the Department of Labor reported, coming in notably higher than the 3.6% increase forecast by analysts surveyed by MarketWatch. This represented a substantial acceleration from the 3.4% annual rate recorded in August, marking one of the final major economic reports delivered to the public and policymakers before voters head to the polls on November 3.
Inflation picked up pace on a sequential, month-over-month basis as well, accelerating from 0.4% in August to 0.6% last month. According to Wednesday’s report, gasoline costs accounted for more than half of the overall monthly jump, surging 9.1% on a monthly basis alone.
Energy prices have experienced severe upward pressure since the United States and Israel launched military attacks against Iran in late February. Those strikes prompted Tehran to retaliate by blocking off the Strait of Hormuz, a narrow and vital maritime chokepoint that serves as a primary global route for oil and gas shipments.
As a result of the prolonged Middle East conflict, average retail prices at U.S. gasoline pumps have surged by more than 45% since the war began, climbing to $4.33 per gallon, according to data compiled by the American Automobile Association (AAA). Diesel prices have experienced an even steeper escalation, spiking by 67.7% over the same period. This dramatic increase in diesel fuel has significantly boosted the cost of transporting goods across the country, threatening further price spillovers for everyday consumers as higher shipping expenses are passed down retail supply chains.
"Again, the Iran-U.S. conflict has led to higher motor fuel costs that everyone is experiencing," ING economist James Knightley told Agence France-Presse (AFP) following the release of the government data. "The U.S. is also seeing substantial increases in airline fares," he noted, adding that these transportation-related increases will likely contribute to additional price pressures in the coming months.
The broad inflationary pulse is also being sustained by broader macroeconomic resilience. With the underlying U.S. economy remaining robust—bolstered by massive corporate and government spending linked to the artificial intelligence sector, which continues to drive high demand for advanced semiconductor chips and skilled labor—economists warn that these elevated costs could continue filtering through to American households for the foreseeable future.
Even when stripping out volatile food and energy prices to gauge the underlying trend, core CPI still posted a notable gain, rising 2.6% from a year ago.
Despite the unwelcome inflation surprise, Knightley said he does not expect the latest report to prompt the Federal Reserve to rush into raising interest rates at its upcoming policy meeting scheduled for October 27-28. Several Federal Reserve policymakers have recently suggested that the central bank does not need to implement back-to-back interest rate increases, instead favoring a cautious, slow, and steady approach to monetary policy normalization.
Industries that are particularly sensitive to shifts in borrowing costs, such as the housing market, are already feeling significant pressure from the higher interest rate environment established over recent cycles.
"I think the Federal Reserve just wants to be a little bit careful and cautious in terms of its policy tightening," Knightley explained, noting that the central bank will likely weigh the ongoing geopolitical supply shocks against broader domestic economic indicators before making its next definitive move.