In the constant battle between environmental protection and commercial exploitation, President Barack Obama has delivered a decisive victory for conservation. But it may be only temporary.

The president has defined more than 12 million acres of the Arctic National Wildlife Refuge as wilderness. That designation, unless Congress overturns it, would place the fragile public land permanently off limits to private development.

As its name suggests, ANWR is home to an impressively diverse array of wildlife. Alaskan natives hunt there for sustenance. The refuge’s 1.5 million-acre coastal plain also is believed to have huge oil deposits.

Threatening this pristine wilderness with massive disruption to permit resource extraction, as oil companies demand, would require an urgent justification to develop a new domestic source of energy that does not exist at the moment. American consumers are using less oil, alternative-energy sources are becoming more cost-effective and dependence on foreign oil is decreasing as oil and gas production has risen in the United States, including in Pennsylvania, with hydraulic fracturing.

Mr. Obama is using his power to protect the refuge, but the law permits Congress to reject his order. Doing so, in the absence of an urgent threat to U.S. energy security, would leave no doubt about the priorities of those who control Congress.

Alaskans who want to be left alone to drill complain that the president’s actions infringe on their “sovereignty.” But national resources such as ANWR are held in trust for all Americans. A state’s rights argument is not compelling here. The president is right to protect this priceless wilderness.

First Published: February 3, 2015, 5:00 a.m.