WASHINGTON — Oil prices jumped Tuesday for the second straight day and gas prices moved higher in the United States, underscoring the threat of rising inflation posed by the Iran war.

Coming after nearly five years of elevated costs, even a modest pickup in prices could further sour many Americans on the economy and heighten the affordability concerns that have become a top political issue.

On Tuesday, U.S. oil prices rose more than 5% to $75.22 a barrel in afternoon trading. Gas prices jumped 11 cents to $3.11 a gallon on average nationwide, according to AAA.

A key issue, economists say, is how long the conflict lasts and whether shipping routes, such as the Strait of Hormuz, at the mouth of the Persian Gulf, is closed. About one-fifth of the world’s oil and natural gas is shipped through the Strait. Even a war of a few weeks might not push up inflation or weaken the economy very long. But should it last for a few months, inflation would likely worsen — perhaps topping 3% for the first time since early 2024.

Here are some ways the war could worsen the economy.

Inflation has lingered

While some measures of inflation have cooled in recent months, the Federal Reserve’s preferred measure has been stuck at about 3% for roughly a year. That is above the central bank’s 2% target, and has occurred even as gas prices fell steadily in 2025.

Should gas prices rise significantly, air fares could also increase as airlines face bigger fuel costs.

Shipping would also become more expensive, which could add to grocery prices. Oil is also used in chemicals and plastics and in many industrial processes, so higher prices could spread.

Natural gas prices have also risen sharply, after a liquid natural gas plant was shut down in Qatar.

That could raise electricity prices in the U.S. Natural gas has already gotten 10% more expensive in the past year, thanks in part to spiking energy usage by data centers powering AI.

Still, economists noted that the U.S. economy is not as oil-dependent as it has been in the past, with most Americans now working in services, rather than manufacturing.

And other factors may help keep oil price increases relatively limited. Rory Johnston, founder of Commodity Context, an oil analytics firm, pointed out that oil inventories were quite high before the conflict, which helped keep prices in check.

That’s in sharp contrast to the winter of 2022, he said, when post-COVID supply chain problems had already pushed up oil costs even before Russia’s invasion of Ukraine caused a much bigger spike.

For every $10 increase in the price of a barrel of oil, economists estimate that U.S. gas prices would rise about 25 cents. Should prices top $100 a barrel, gas would move closer to $3.50 a gallon or higher.

Even without a big inflation spike, a major risk for Trump is that Americans sour on his economic leadership.

According to surveys, Americans already have a gloomy outlook on the economy, largely because of the lingering effects of the price spikes of the past five years.

A protracted conflict in Iran that raised gas prices would likely make it worse, said Alex Jacquez, chief of policy and advocacy at the Groundwork Collaborative and an economic adviser to the Biden White House.

And with inflation potentially headed higher, the Federal Reserve could further delay any additional interest rate cuts.