After posting 1,200 National Guard troops at the US-Mexico border to stop crossings of undocumented immigrants, the Department of Homeland Security will draw down those forces by 75% and shift the mission considerably:

The drawdown, which the department characterized as a “transition,” will begin in January and should be completed by March. Several lawmakers told CNN the number of National Guard troops on the border will be cut from 1,200 with responsibilities mainly on the ground to 300 who will support the border mission in the air.

The Department of Homeland Security said the change is possible because of a jump in the number of Border Patrol officers in the region, an increase in technology and a drop in apprehensions at the border.

Of course, the rabid xenophobes in the Republican caucus disagreed with the moves, claiming we don’t have “operational control” of the border and that more troops are actually needed for security. But border arrests have dropped sharply, down 53% from 2008 to today, and 80% from 2000 levels. What’s more, Border Patrol officers have doubled in size since 2004.

But don’t think that the militarization of the border will go away, even with National Guard troops leaving the picture. As the release says, the remaining troops will “support the border mission in the air.” That includes, according to DHS, “adding a number of new multi-purpose aerial assets” that carry the “latest surveillance and reconnaissance capabilities.” Or, if you prefer, drones:

This is the semi-covert cutting edge of homeland security, where federal law enforcement authorities are rapidly expanding a military-style unmanned aerial reconnaissance operation along the U.S.-Mexico border — a region that privacy watchdogs say includes a lot of American back yards.

Fans of the Predators say the $20 million aircraft are a perfect platform to keep a watchful eye on America’s rugged borders, but critics say the drones are expensive, invasive and finicky toys that have done little — compared with what Border Patrol agents do on the ground — to stem the flow of illegal crossers, drug smugglers or terrorists.

Much like the rest of our military commitments, we are moving from a manpower-intensive mission to a secret, off-books, robot war mission, with unmanned aerial vehicles dominating. We’ve already heard about the increasing use of drones on US soil to aid law enforcement, so drones on the border was a logical and expected step. That doesn’t make it particularly appealing.