WASHINGTON — President Trump’s defense secretary thought the idea was outrageous.
In the spring of 2020, Mark T. Esper, the defense secretary, was alarmed to learn of an idea under discussion at a top military command and at the Department of Homeland Security to send as many as 250,000 troops — more than half the active U.S. Army, and a sixth of all American forces — to the southern border in what would have been the largest use of the military inside the United States since the Civil War.
With the coronavirus pandemic raging, Stephen Miller, the architect of Mr. Trump’s immigration agenda, had urged the Homeland Security Department to develop a plan for the number of troops that would be needed to seal the entire 2,000-mile border with Mexico. It is not clear whether it was officials in homeland security or the Pentagon who concluded that a quarter of a million troops would be required.
The concept was relayed to officials at the Defense Department’s Northern Command, which is responsible for all military operations in the United States and on its borders, according to several former senior administration officials. Officials said the idea was never presented formally to Mr. Trump for approval, but it was discussed in meetings at the White House as they debated other options for closing the border to illegal immigration.