If President Trump gets his way, the auto industry’s transition to electric vehicles is about to go into reverse. It will eliminate tax credits for electric vehicle purchases, federal subsidies for chargers, and subsidies and loans to help convert production lines and build battery factories.

Executive orders that Mr. Trump’s Inauguration Day releases represent a sweeping rejection of the centerpiece of former President Joseph R. Biden Jr.’s multibillion-dollar agenda. to address climate change, which Republicans presented as a campaign to ban gasoline-powered cars.

The orders also pose a challenge to automakers that have invested billions of dollars in electric vehicles, in part because the Biden administration has encouraged them to do so. But some of the orders appear to bypass Congressional or federal rulemaking procedures, which could leave them vulnerable to lawsuits and even resistance within the Republican Party.

Although intended as a way to revive the U.S. auto industry, the orders could cause U.S. automakers to lag if they scale back their electric vehicle programs while Asian and European automakers continue to refine the technology, analysts said. Already, 50 percent of car sales in China are electric or plug-in hybrids, and Chinese automakers like BYD are selling more cars around the world, taking customers away from established automakers, including American manufacturers.

The executive order titled “Unlocking American Energy” signed by the president on Monday directs federal agencies to immediately halt the disbursement of funds appropriated by Congress that were part of Biden’s efforts to push the auto industry toward zero-emissions vehicles. Among other things, the funds helped states install fast charging stations along major highways.

The main climate law Mr. Biden’s Inflation Reduction Act also provided tax credits of up to $7,500 for buyers of new electric vehicles and $4,000 for buyers of used models. The credits have effectively equalized the cost of buying some electric cars with the prices of cars with gasoline or diesel engines.

Mr. Trump also reversed an ambitious executive order by Mr. Biden that required 50 percent of new vehicles sold in 2030 to be fully electric, plug-in hybrids or vehicles powered by hydrogen fuel cells.

And Mr. Trump said the administration would seek to revoke California’s authority to set air quality standards that are stricter than federal rules. This would have a far-reaching effect. California aims to have 100 percent of new car sales be electric by 2035, and at least 17 other states are copying some of its standards.

“The impact of this is going to be significant,” said Shay Natarajan, a partner at Mobility Impact Partners, a private equity firm that invests in sustainable transportation.

If demand for electric vehicles declines, as is the case in other countries like Germany that have cut incentives, she noted, automakers could be left with expensive, underutilized electric vehicle and battery factories.

“Federal financing for electric vehicle and battery manufacturing will be more difficult to come by, increasing the risk of stranded capital for manufacturing projects already underway,” Ms. Natarajan said in an email.

Representatives of the fossil fuel industry celebrated the president’s action, while environmentalists lamented what they said was a serious step backwards in efforts to reduce greenhouse gas emissions and reduce urban air pollution caused by cars.

“This is a new day for American energy,” Mike Sommers, president of the American Petroleum Institute, said in a statement, “and we applaud President Trump for moving quickly to chart a new path where American oil and natural gas are accepted, not limited.”

Katherine García, transportation expert at the Sierra Club, said, “Repealing vehicle emissions protections hurts our health, our wallets, and our climate. We will fight him every step of the way.”

But the ultimate effect may not be as sweeping as the violent language in Mr. Trump’s executive orders suggests.

Funds for encouraging the sale and production of electric vehicles are contained in a law that cannot be unilaterally repealed by the president. Mr. Trump also cannot revoke the rules that the Treasury Department and other government agencies have established to determine how the money will be distributed with the stroke of a pen. Any attempt to end the painstaking process of proposing new regulations that includes seeking public comment will almost certainly trigger credible legal challenges.

The Energy Department has agreed to lend billions to automakers like Rivian, which will get $6 billion for a plant near Atlanta to make electric SUVs. The loan agreements, some finalized in the final days of the Biden administration, are binding contracts.

Much of the money flows to congressional districts in states such as Georgia, Ohio, South Carolina and Tennessee where Republicans dominate local politics. Their representatives may be reluctant to repeal laws that have brought jobs and investment to their districts. That’s a challenge for Republican leaders fighting for slim majorities in the House and Senate.

Ultimately, individuals and families will decide which cars to buy. Electric vehicles and plug-in hybrids are gaining market share not only because of subsidies, but also because they offer quick acceleration and lower fuel costs. Fossil-fueled cars are losing share, although that could change if financial incentives for battery-powered cars and trucks are removed.

The sudden change in political direction presents a dilemma for car manufacturers. Some may welcome the president’s promises to lift emissions and air quality standards that force manufacturers to sell more electric cars than they would like. But ending federal subsidies could disrupt their financial planning when most are struggling to make ends meet or increase profits.

The shift in electric vehicle policy adds to an atmosphere of uncertainty and danger heightened by the president’s promise to impose 25 percent tariffs on goods from Canada and Mexico, which are major suppliers of cars and auto parts to the United States.

The U.S. auto industry “will be crushed by tariffs on assembled vehicles or parts at this level,” Carl Weinberg, chief economist at High Frequency Economics, said in a note to clients on Tuesday.

Some automakers seemed to applaud the president’s actions, while others were noncommittal.

“President Trump’s clear focus on policies that support a strong and competitive manufacturing base in the United States is extremely positive,” Stellantis, which owns Dodge, Jeep, Ram, Chrysler and other brands, said in a statement.

Mary T. Barra, CEO of General Motors, congratulated Mr. Trump on Monday on the X and said the company “looks forward to working together on our shared goal of a strong American auto industry.”

There is no sign that Elon Musk — the chief executive of Tesla and head of what Mr. Trump calls the Department of Government Efficiency — is using his influence to blunt the attack on electric vehicles. Tesla accounts for just under half of all electric cars sold in the United States, and nearly all of its vehicles qualify for a $7,500 tax credit.

Four of the 16 cars and trucks that can be purchased with the help of this tax credit are manufactured by Tesla. GM is the only car manufacturer with more than five eligible models. No other company has more than two eligible vehicles.

Mr. Musk has previously said that the government should get rid of all subsidies and that Tesla would suffer less than other automakers. But analysts note that Tesla’s sales and profits would be hit hard if Mr. Trump has successfully repealed or reduced the electric vehicle tax credit, California’s clean air waiver and other such policies.

Tesla did not respond to a request for comment.

During an appearance before Trump supporters in Washington on Monday, Mr. Musk, who is also the chief executive of SpaceX, gloated that the president had promised to send astronauts to Mars. “Can you imagine how great it will be for astronauts to plant a flag on another planet for the first time?” Mr. Musk said. He did not mention cars.