The White House predicted in 2017 that lease sales in the refuge would generate $1.8 billion over a decade, but revenue estimates ever since, including the government’s, have been substantially lower. The first oil and gas leases could be sold within months.

Officials also played down evidence that the refuge might not have much oil, and pushed scientists to provide studies and other information so quickly that some expressed concern.

Background: The debate over drilling in the refuge, which opponents say could damage one of the largest expanses of pristine land in the U.S., goes back decades. Government studies in the 1990s suggested as much as 11 billion barrels of oil could be recovered, but findings from the area’s only exploratory well have been kept confidential.

N.R.A. gets results with White House call

After speaking with the chief executive of the National Rifle Association on Tuesday, President Trump said, “A lot of the people that put me where I am are strong believers in the Second Amendment, and I am also.”