MACV used this opportunity to field its latest technology against the North Vietnamese. A sensor-driven, anti-infiltration system known as Operation Igloo White was in the process of being field tested in Laos as the siege of Khe Sanh began. Westmoreland ordered that it be employed to detect PAVN troop movements near the Marine base and the system worked well. By March, the long-awaited ground assault against the base had failed to materialize and communist forces began to melt back toward Laos. MACV (and future historians) were left with only questions. What was the goal of the PAVN? Was the siege a real attempt to stage another Dien Bien Phu? Or had the battles near the border (which eventually drew in half of MACV's maneuver battalions) been a diversion, meant to pull forces away from the cities, where another PAVN offensive would soon commence?