The reason: The United States’ capacity for refining oil into gasoline is declining, a trend that appears irreversible — for reasons that include climate change. But the nation’s appetite for fuel is holding firm, no matter all the predictions of a future filled with electric cars.

The result is a domestic gasoline supply on a hair trigger, making the nation more vulnerable to fuel panics that would resemble last year’s hacker-driven shutdown of the Colonial Pipeline, while feeding inflation and angering voters. Since early 2020, the United States’ fuel-producing capacity has fallen by nearly 1 million barrels per day, or about 5 percent.

“We are going to be operating a shrunken, old and in-need-of-repair refining system a lot harder,” said Bob McNally, head of consulting firm Rapidan Energy and former senior director for international energy on the National Security Council in the George W. Bush administration. “Future presidents and administrations are going to be absolutely bedeviled by high gasoline prices.”