There's ample evidence that the president can't change gas prices. So why do politicians claim he can? It's an old trope:
This happens every few years, and every few years it’s total nonsense.
Since it’s happening again, and since the press seems once again more concerned about the political implications of rising gas prices than with actual forces driving them up, TPM turned to energy expert Robert Rapier for an analyst’s view.
[T]here’s very little policymakers can do today or could have done in the recent past to upset the price increase. In fact, thanks to a persistently low gas tax, the U.S. remains one of the cheaper places to fill up in the world.
“They could subsidize it, they could tax it more or tax it less, they could put import tariffs on oil coming in or export tariffs going out,” Rapier said. “Outside of forcing a recession in China,” Rapier joked, that’s pretty much it.
The only way to spend less on gas, then, is to use less gas. But that would require entirely different land and transport policies for most of the U.S., so we'll just have to blame someone else.