One problem with surrounding a powerful fighting force is containing them at the point of their counter-attack. The besieging force needs to carry out an attack themselves, to force some sort of withdrawal, and then mass sufficient strength at the point of counter-attack to stop it. Even if the probable defense direction of withdrawal is an exposed road, such as the MSR (Main Supply Route) at the Reservoir, sufficient surrounding force needs to be maintained to prevent the besieged from forcing a different bypass. And even in the road is taken, a determined fighting defense will be very hard to contain at any single point, even with well-placed roadblocks supported by enfillading fire from surrounding heights. Although surrounded by far larger numbers of troops, resolute and veteran troops, the Marines simply took their losses, took those high grounds, crushed the roadblocks, and kept going. For thirty-five bloody miles.
