Pakistan, Sept. 25 -- Eight drones entered Pakistani airspace from Afghanistan on Wednesday, four near Torkham and four near Kohat, forcing the armed forces to engage an aerial threat at the same time that Khyber Pakhtunkhwa is already absorbing militant infiltration, suicide attacks and cross-border fire. All eight were brought down. Pakistan answered hours later with strikes on 10 locations inside Afghanistan which, according to Information Minister Attaullah Tarar, were being used to launch and store the drones. The security problem on the western frontier has plainly moved beyond porous borders and militant hideouts. Pakistan is now having to defend its airspace as well.

Nor was Wednesday an isolated episode. Security sources say fou...