What did Donald Trump do today?

He scrambled to get states to go along with his latest band-aid on inflation.

Last night, appearing at a campaign rally in what is normally the rock-solid Republican state of Nebraska, Trump signed an executive order that would temporarily allow trucks and other over-the-road vehicles to use agricultural diesel. The fuels are virtually the same chemically, but agricultural diesel is dyed red to indicate that it was not subject to the usual federal fuel tax. Normally, only machinery that stays on a farm, like tractors and harvesters, can use dyed diesel.

The idea was that, since federal tax on diesel comes to about 24 cents per gallon, truckers would pay that much less at the pump. The average prices of diesel fuel is about $6.20 as of this week, up 71% from the day Trump took office in 2025. 

But the plan was almost completely unworkable from the start, as trucking companies are saying today. Among the problems:

• It's not widely available. Few of the service plazas that long-haul trucks use sell dyed diesel. 

• There aren't enough pumps for it. Truck stops that do sell dyed diesel generally only have one pump for it. Even if that tank were kept full, there would be long lines for it.  

• The law of supply and demand hasn't been repealed. Giving anyone the opportunity to buy tax-free fuel won't mean everyone pays the lower of two prices. It means that the lower price will rise towards the higher price in proportion to its availability. 
  
  In other words, adding a splash of tax-free diesel onto the market will only lower overall prices a tiny bit.  

• Using it voids warranties. Most vehicles not intended for agricultural use are covered by warranties that strictly forbid using agricultural or heating oil. While they will work, there are meaningful differences in the formulations that can damage or degrade finely-tuned engines.

But the main obstacle is that the states also tax and regulate dyed diesel, and it is flatly illegal to "run red" in many of them, regardless of federal law, and there are steep fines and frequent inspections. Trump's temporary suspension of tax collection, which will end shortly after the election that has him campaigning in ruby-red Nebraska, also doesn't change the fact that most states charge sales tax on all fuel, including dyed diesel.

And the Trump administration apparently didn't give states any warning that this move was coming, the better to make a splashy announcement and order-signing last night.

That's why today, the Trump administration was scrambling to persuade state governments to go along with the move, and to suspend their own enforcement. Some have indicated that they'll go along with it—but others won't, which will leave gaps on the map where it will be illegal to drive with red diesel in the tank. That means that for most interstate shipping companies, it won't be worth the trouble trying to save fractions of a cent per gallon by buying up agricultural diesel.  

There's one other problem with Trump's claim from the stage last night that he was suspending the tax: he's not actually doing that in all. In reality, the order only defers collection, with a vague hint that the administration would explore ways to forgive it. That's because Trump doesn't have any legal authority to simply ignore taxes established by law. Businesses would have to keep separate records for the dyed diesel or risk having to pay penalties and interest when the order expired.

Why does this matter?

• Desperately lurching towards anything that sounds like it might be popular is a stupid way to govern. 

• A 24-cent tax is not why diesel fuel has gone up almost $3 a gallon since Trump returned to office.
   
• The traditional way to try to bribe someone is with something they'd want.