Trump's approval ratings would likely take a direct hit from a gasoline tax hike

• The federal government has not levied a gasoline tax increase in 24 years.
• Presidential approval ratings have been known to drop when gas prices rise.
• Voters in a recent Harvard-Harris poll strongly oppose a gasoline tax hike.

A customer prepares to pump gasoline at an Arco gas station in Mill Valley, Calif.

Getty Images

President Donald Trump in an interview Monday said he would consider a gasoline tax increase if it paid for highway infrastructure. The new president may not realize that the federal government has not imposed one since 1993.

And there's one big reason why: When gasoline prices go up, presidential approval ratings go down.

Source: Strategas

That's why Dan Clifton, head of policy research at Strategas, believes the idea floated by Trump this week is a nonstarter.

"We remain highly skeptical of Congress working in a bipartisan manner on tax reform even if infrastructure is included. And a gasoline tax increase won't be enough for Democratic support if tax rates are being lowered in a meaningful way. Consumers are very sensitive to gasoline prices and historically voters have rejected ballot initiatives to raise the gasoline tax even when the money is used for infrastructure," he wrote in a note.

The Harvard-Harris poll asked voters what they thought about a series of possible surcharges, and one of the least popular was a gasoline tax, with 77 percent against it. The online poll of 2,027 voters was conducted in mid-April. The most popular surcharge? Taxing the rich.

Voters' reaction to various tax surcharges

Source: Harvard-Harris poll, April, 2017

Meanwhile, gasoline prices in the U.S. are falling but they are still above last year's levels. At the same time, demand has been dropping even in the last few weeks, usually a good time for driving demand.

"Any time prices go up, it would cause some sort of reaction, and it seems like it's doing that," said Fred Rozell, director of retail pricing at Oil Price Information Services. A federal gasoline tax increase could hit gasoline demand depending on how large it is, he said.

The national average price at the pump for regular unleaded was $2.37 per gallon Tuesday, down from $2.41 per gallon last week, according to AAA.

Some analysts say the longer-term trend of a decline in gasoline demand may be related to more efficient cars. Rozell said it could also be longer-term trends, such as people working from home.

U.S. gasoline demand

Source: Oil Price Information Service