There were several reasons for the deactivation of the KSCB since, for all practical purposes, the base had outlived its usefulness. The rationale endorsed by General Cushman and General Rosson was threefold. First, the enemy had reduced his forces and changed his =modus operandi= in the Khe Sanh area. Secondly, the NVA artillery in Laos had accurately targeted the base and access road which compounded the casualty and resupply problems. Finally and most important, General Cushman had sufficient assets in June to pursue the mobile offensive strategy which he had advocated strongly for such a long time. Two U. S. Army divisions (i.e. 1st ACD and the 101st Airborne) with their inherent helicopter resources had been shifted to III MAF and, during March and April, the tremendous logistics burden associated with the introduction of these 50,000 men into northern I Corps had been alleviated. Since he had sufficient maneuver elements to go on the offense in western Quang Tri Province, General Cushman no longer needed five battalions buttoned up in Khe Sanh.(230) An additional consideration for the abandonment of the base was President Johnson's announcement on 31 March that the U. S. would end air strikes in North Vietnam.[76] While the decision was a major step toward peace, it also enabled thousands of NVA support personnel who were responsible for road repair in North Vietnam to move further south. These workers constructed a network of infiltration arteries which bypassed the combat base and the continued policy of positioning static Allied defense installations in the path of these routes would have been inefficient and undesirable. In this regard, the best defense was a highly mobile offense and while a forward operating base for such operations was essential, the LZ Stud/Ca Lu area was much better suited than Khe Sanh.(231) By the time PEGASUS was over, LZ Stud was in full operation. The airstrip was extended to accommodate C-123s, a Force Logistics Area was established, and local defenses were strengthened. The base was outside the range of the North Vietnamese 130mm and 152mm guns in Laos and the stretch of Route 9 from Ca Lu to the Rockpile and eventually Dong Ha was easier to keep open. Thus, two factors--enemy shelling and resupply problems--which had negated the effectiveness of Khe Sanh as a base of operations were absent at LZ Stud.