Rep. James Clyburn (D-S.C.), the Assistant Democratic Leader and one of the most senior Black lawmakers in the House, used a Friday morning post on X to warn that record-high diesel prices tied to President Donald Trump’s war in the Middle East are on the verge of spreading into the cost of nearly everything American consumers buy. The veteran South Carolina Democrat’s post, published at 8:13 a.m. on September 18, 2026, tied the ongoing conflict directly to fuel costs and cautioned that the economic fallout has not yet fully reached households.
Clyburn’s post read in its entirety:
“Diesel prices are breaking records every day due to Trump’s war in the Middle East. In the coming weeks, that’s likely to trickle down to everything Americans buy. Brace yourselves.”
Clyburn linked his post to a CNBC report published Thursday detailing how the surge in diesel costs is beginning to work its way through the broader U.S. economy, from freight and rail to groceries and home heating.
Diesel Hits a New All-Time High Amid a Global Refining Crunch
According to the CNBC report Clyburn cited, diesel fuel hit an all-time high of $6.31 per gallon on Wednesday, September 16, extending a steady upward march that began with the outbreak of the U.S.-Iran war earlier this year. David Russell, global head of market strategy at TradeStation Group, told CNBC that diesel is “the economy’s single most universal tangible input,” meaning that freight haulers are the first to feel the pain but far from the last. The chief commercial officer for Norfolk Southern railroad said at a Morgan Stanley conference this week that diesel in California had already reached $8 a gallon.
Jack Buffington, an associate professor of supply chain management at the University of Denver, told CNBC that the spike is driven less by crude oil prices than by a collapse in global refining capacity, with roughly 20% of the world’s refining capacity currently offline due to damage in Russia and the Middle East. Buffington cautioned that even if fighting stopped immediately, diesel prices would not fall quickly, estimating it could take a year or longer to return to the $4-per-gallon range.
From the Fuel Pump to the Grocery Aisle
The CNBC report Clyburn referenced detailed how the diesel spike is beginning to touch nearly every corner of the consumer economy. Jeff Lenard of the National Association of Convenience Stores said retailers are currently absorbing roughly 15 cents a gallon in added costs rather than passing them on to customers, while Carmit Glik, CEO of the digital freight forwarder Ship4wd, said diesel “moves through freight rates, farm equipment, food delivery, and home heating” before consumers ever see the impact directly. Costco has already moved to limit how much motor oil its members can purchase.
The report also warned that home heating oil, widely used in the Northeast, tracks closely with diesel prices. Mark Wolfe, executive director of the National Energy Assistance Directors Association, projected customers could pay as much as 31% more this winter if prices hold, and noted his organization’s push for additional federal heating assistance funding faces long odds with the House in recess until November.
Trucking giant J.B. Hunt’s chief financial officer, Brad Delco, told CNBC the company has experienced “some of the most radical and abnormal swings” in fuel costs it has ever seen, warning of a resulting $10 million financial headwind and lower earnings ahead. Federal Reserve Chair Kevin Warsh separately cited the “crack spread” — the gap between crude oil prices and finished fuel prices — as a factor behind the central bank’s decision this week to raise interest rates.
Part of a Broader Pattern From Clyburn
Friday’s post is the third in a week in which Clyburn has used social media to link the Iran war directly to the cost of living for American families. On Tuesday, September 15, Clyburn cited a new Congressional Budget Office report finding the war has cost taxpayers an average of $246 million per day, accusing the administration of “squandering our tax dollars” on what he called a “failed Iran War” even as Americans face rising costs at home.
Two days later, on Thursday, September 17, Clyburn posted that “due to the President’s debacle in Iran, interest rates are unfortunately heading back up,” warning of higher borrowing costs for car loans, credit cards, and mortgages, while criticizing Trump for being “more consumed with renovating the White House” — which the president has referred to as a “palace” — and criticizing House Republicans for what Clyburn called canceling legislative work in Washington for nearly eight weeks.
That post followed the Federal Reserve’s decision to raise interest rates for the first time since 2023. The average 30-year mortgage rate stood at 7.37% as of Thursday, according to Zillow data, nearly two full percentage points above the 5.75% average recorded in early March 2026, shortly after Trump launched military operations against Iran.
The Underlying Cost Figures Driving the Criticism
The CBO’s analysis, which Clyburn cited in his Tuesday post, found that higher energy costs tied to the war contributed to a 2.3 percentage point rise in inflation, to 5.3%, in the second quarter of 2026. More than half of the war’s costs have gone toward replacing munitions expended in the fighting, with increased flying hours adding $10.4 billion and war-related fuel price increases adding another $2.7 billion. The CBO’s own crude oil projections, built on data through mid-August, may understate the war’s ongoing impact, given that Brent crude has been trading above $103 a barrel rather than the $84 the agency projected for year’s end.
A separate analysis from the Center for American Progress found that the war has pushed long-term interest rates up by roughly 0.5 percentage points, adding at least $48.1 billion in borrowing costs across households, businesses, and the federal government in 2026 alone, with the federal government projected to pay at least $30.8 billion more in interest on new debt this year because of war-related inflationary pressure.
Separately, a Brown University Watson School cost tracker found U.S. consumers have paid an extra $100.9 billion on gasoline and diesel combined since the war began in late February, or roughly $770 per household, a figure researchers say will likely keep climbing as fuel costs remain elevated. Tom Kloza, chief energy adviser at Gulf Oil, told CNN that the coming fall “is going to be the most expensive ever for gasoline, but really for diesel.”
A Wider Democratic Effort to Tie the War to Household Costs
Clyburn is one of several congressional Democrats who have pressed the administration on the war’s economic toll in recent months. Senate Democrats including Alex Padilla, Elizabeth Warren, Jeff Merkley, and Minority Leader Chuck Schumer sent a letter to the CBO earlier this year demanding a transparent accounting of the war’s costs, noting gas prices had already topped $6 a gallon in California.
House Democrats Jared Huffman, Robert Garcia, Frank Pallone Jr., Angie Craig, and Don Beyer Jr. sent a joint letter to Trump asserting that consumer prices had reached their fastest growth in nearly two years as war-related oil costs fed into the broader economy. More recently, Sen. Elissa Slotkin led nearly the entire Senate Democratic caucus — 46 members — in demanding that the Pentagon provide a full public accounting of where war spending has gone, calling it “the bare minimum that any American would expect.”
Administration Pushback and Signs of Relief
The White House has disputed that the war bears primary responsibility for rising fuel costs. U.S. Secretary of Transportation Sean Duffy argued in a Fox News interview that Russia’s halted diesel exports amid the Ukraine war are a bigger factor, and said Trump’s push for “American energy dominance” was working to bring prices down rather than up. Separately, White House Council of Economic Advisers Chair Christopher Phelan told CNBC this week that the Fed’s rate hike itself was a “mistake,” reflecting the administration’s frustration with the central bank’s refusal to lower rates despite pressure from Trump.
There have been modest signs of potential relief. Saudi Arabia has taken steps to bring more oil to market, a move that sent crude prices lower on Thursday, and forecasters are pointing to a strong El Niño pattern that could bring milder winter temperatures to the Northeast, potentially easing the pressure on home heating oil demand. Still, supply chain strategist Steve Blough of Infios warned that any additional disruption — a late-season hurricane or a new geopolitical shock — could push prices higher still, and cautioned that “every mile matters” once diesel reaches current levels.
What Comes Next
With Congress in an extended recess ahead of the November 3 midterms and refining capacity showing no sign of a quick recovery, the diesel price spike Clyburn highlighted Friday is likely to remain a central flashpoint in the campaign season ahead. JPMorgan analysts wrote in a Thursday note that “we don’t have a baseline view” on how the oil market will evolve, adding that assumptions the disruption is temporary are “becoming increasingly difficult to sustain” — a level of uncertainty that leaves both the price at the pump and the political fight over who bears responsibility for it unresolved.