For the last six months, President Biden and his top advisors have obsessed over gasoline prices, for obvious reasons. That's because no single price rattles consumers as much as the cost of gas, which crept up to a new record high of $5 per gallon in June. So it comes as no surprise that soaring gas prices corresponded directly with Biden's sinking approval rating.

Since then, gas prices have fallen by about $1.10 per gallon. Biden may have helped a little by releasing oil from the US strategic reserve. Market forces, tough, have been a bigger factor. Still, that hasn't stopped Biden from touting the drop in prices and claiming he deserves the credit.

But Biden has largely ignored another important type of fuel: diesel fuel, which is critical for the production and transportation of many everyday products. There's a reason for Biden's silence: Diesel prices remain uncomfortably high, and they're contributing to food inflation and other consumer pain points. Around the same time gas hit $5, diesel hit a record high of $5.81 per gallon. Gas prices are now 22% below their peak, but diesel is just 8% lower. On a year-over-year basis, gas prices are up 15% while diesel is up 43%.

High diesel prices are a kind of hidden inflation, because most consumers never buy diesel. But it’s an important input in the production and transportation and of many things, including food and consumer goods shipped around the country. Inflation, at 8.2%, is still uncomfortably high, a huge reason Biden’s approval rating is underwater and Democrats seem headed for resounding defeat in the midterms. A big part of the reason is rising input costs for everyday consumer products.

The American Farm Bureau Federation sent a letter to Biden on November 4 drawing attention to the problem. “Our nation’s food supply is driven by diesel,” Farm Bureau president Zippy Duvall wrote. “High diesel prices are severely impacting our farmers and ranchers, causing increased costs to consumers, and adding to food insecurity.” While the pace of gasoline inflation has moderated substantially in recent months, food inflation has generally gotten worse, and now stands at 13% year-over-year. Wages are only rising by around 5%, so it takes a bigger chunk of the family paycheck to fill the refrigerator.