American forces would conduct operations against PAVN forces, pushing them further back into the countryside away from the heavily populated coastal lowlands. In the backcountry the U.S. could fully utilize its superiority in firepower and mobility to bleed the enemy in set-piece battles. The cleaning-out of the NLF and the pacification of the villages would be the responsibility of the South Vietnamese military. The adoption of this strategy, however, brought Westmoreland into direct conflict with his Marine Corps commander, General Lewis W. Walt, who had already recognized the security of the villages as the key to success. Walt had immediately commenced pacification efforts in his area of responsibility, but Westmoreland was unhappy, believing that the Marines were being underutilized and fighting the wrong enemy. In the end, MACV won out and Westmoreland's search and destroy concept, predicated on the attrition of enemy forces, won the day.