Since 2010, over 1,200 national guard troops have been patrolling the U.S.’s southwestern border. This week, the Obama administration announced that many of those troops are leaving.

More from CNN:

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.

The announcement doesn’t sit well with enforcement-happy lawmakers in the region, like Texas Republican Rep. Lamar Smith.

"If the Obama administration’s goal is border security, their actions undermine their objective," Smith said in a written statement, according to CNN. "We should keep guardsmen on the ground until the Border Patrol can gain operational control of the majority of the U.S.-Mexico border."

Despite those concerns, the FBI’s own statistics have shown that violence along the border is on the decline. The murder rates in cities long the border, including San Diego, Phoenix, Tucscon and El Paso, have all declined faster than the national murder rate in recent years.