President Biden wants more of America’s cars and trucks to run on electricity, not gas. His administration has pushed that goal on multiple fronts, including strict new regulations of auto emissions and lavish new subsidies to help American consumers take as much as $7,500 off the cost of a new electric vehicle.

Mr. Biden’s aides agree that electric vehicles — which retail for more than $53,000 on average in the United States — would sell even faster here if they were less expensive. As it happens, there is a wave of new electric vehicles that are significantly cheaper than the ones customers can currently buy in the United States. They are proving extremely popular in Europe.

But the president and his team do not want Americans to buy these cheap cars, which retail elsewhere for as little as $10,000, because they are made in China. That’s true even though a surge of low-cost imported electric vehicles might help drive down car prices overall, potentially helping Mr. Biden in his re-election campaign at a time when inflation remains voters’ top economic concern.

Instead, the president is taking steps to make Chinese electric vehicles prohibitively expensive, in large part to protect American automakers. Mr. Biden signed an executive action earlier this month that quadruples tariffs on those cars to 100 percent.

Those tariffs will put many potential Chinese imports at a significant cost disadvantage to electric vehicles made in America. But some models, like the discount BYD Seagull, could still cost less than some American rivals even after tariffs, which is one reason Senator Sherrod Brown of Ohio and some other Democrats have called on Mr. Biden to ban Chinese E.V. imports entirely.

The apparent clash between climate concerns and American manufacturing has upset some environmentalists and liberal economists, who say the country and the world would be better off if Mr. Biden welcomed the importation of low-cost, low-emission technologies to fight climate change.

Mr. Biden and his aides reject that critique. They say the president’s efforts to restrict Chinese electric cars and other clean-technology imports are an important counter to illegal and harmful trade practices being carried out by Beijing.

And they insist that Mr. Biden’s trade approach will ultimately benefit American jobs and national security — along with the planet.

Here are the policy and political considerations driving Mr. Biden’s attempt to shield American producers from Chinese competition.

Denying Beijing a new monopoly

China already dominates key clean-energy manufacturing in areas like solar cells and batteries. Mr. Biden’s aides want to prevent it from gaining monopolies in similar industries, like electric vehicles, for several reasons.

They include climate concerns. Administration officials say Chinese factories, which tend to be powered by fossil fuels like coal, produce more greenhouse gas emissions than American plants.

There is also a central economic reason to deny China a monopoly: ensuring that electric cars and trucks will always be available, at competitive prices. The Covid-19 pandemic drove home the fragility of global supply chains, as critical products like semiconductors became hard to get from China and other Asian nations that the United States relied upon. Prices for consumer electronics and other products that relied on imported materials soared, fueling inflation.

Biden officials want to avoid a similar scenario for electric vehicles. Concentrating the supply of E.V.s and other advanced green tech in China would risk “the world’s collective ability to have access to the technologies we need to be successful in a clean energy economy,” said Ali Zaidi, Mr. Biden’s national climate adviser.

Shoring up national security

Biden officials say they are not trying to bring the world’s entire electric vehicle supply chain to the United States. They are cutting deals with allies to supply minerals for advanced batteries, for example, and encouraging countries in Europe and elsewhere to subsidize their own domestic clean-tech production. But they are particularly worried about the security implications of a major rival like China dominating the space.

The administration has initiated investigations into the risks of software and hardware of future imported smart cars — electric or otherwise — from China that could track Americans’ locations and report back to Beijing. Liberal economists also worry about the prospect of China cutting off access to new cars or key components of them, for strategic purposes.

Allowing China to dominate E.V. production risks repeating the longstanding economic and security challenges of gasoline-powered cars, said Elizabeth Pancotti, the director of special initiatives at the liberal Roosevelt Institute in Washington, which has cheered Mr. Biden’s industrial policy efforts.

Americans have struggled for decades to cope with decisions by often hostile oil-producing nations, which act as part of the OPEC cartel, to curtail production and raise gasoline prices. China could wreak similar havoc on the electric-car market if it drives other nations out of the business, she said.

If that happens, she said, “reversing that is going to be really difficult.”

Biden needs the energy transition to create jobs

There is no denying that politics also play a huge factor in Mr. Biden’s decisions. Simply put: He is promising that his climate program will create jobs — good-paying, blue-collar manufacturing jobs, including in crucial swing states like Pennsylvania and Michigan.

Mr. Biden is a staunch supporter of organized labor, and is counting on union votes to help win those states. He has pledged that the energy transition will boost union workers. He is betting their support for tariffs meant to protect American manufacturing jobs will dwarf any complaints from environmentalists who want faster progress on reducing emissions.

“One of the constituent groups in the Democratic Party that’s really highly organized, that gets people out to knock on doors, is the labor movement, more so than the environmental movement,” said Todd Vachon, a professor of labor studies at Rutgers University and the author of “Clean Air and Good Jobs: U.S. Labor and the Struggle for Climate Justice.”

Those concerns have come into especially high relief given that many clean energy jobs are with young companies where workers aren’t unionized, he added.

Mr. Biden put those concerns front and center when announcing his tariff decision last week.

“Back in 2000, when cheap steel from China began to flood the market, U.S. steel towns across Pennsylvania and Ohio were hit hard,” he said at the White House. “Ironworkers and steelworkers in Pennsylvania and Ohio lost their jobs. I’m not going to let that happen again.”