Arizona and Texas will be sending 400 National Guard members to the southern border in response to President Donald Trump's Wednesday Executive Order directing the troops to "assist the border patrol" in guarding the nation's existing border fence - and of course the many miles of completely unprotected crossing zones. 

The troops will be armed for self defense "depending on the mission set," according to Brig. Gen. Tracy Norris, commander of the Texas Army National Guard, who added that it was "premature right now to know what the cost will be" of the overall operation.

"Tonight there are National Guard troops moving in support of the border security mission," said chief Pentagon spokesperson Dana White, who added ""The National Guard's efforts will include aviation, engineering, surveillance, communications, vehicle maintenance and logistical support."