The Outlook in July
As the second half of “the year of the offensive” opened in I CTZ, not much had changed. Ground operations had been prolonged and bloody, but If anything the enemy seemed to be gaining in strength; so much so that COMUSMACV had reluctantly formed sundry army units into Task Force OREGON to deal with the southern portions of the zone, allowing the marines to devote full attention to the war along the DMZ. By early fall, SIGINT had begun to detect signs of a renewed enemy buildup along Route 9 near the Laotian border. ARDF fixed subordinate units of the NVA 304th Division, which had risen to fame at Dien Bien Phu, as well as elements of the 320th Division.
The marines farther east, opposed to the anti-infiltration barrier scheme all along, reluctantly began work on the Strong Point Obstacle System (SPOS) segment of the “McNamara Line.” (See "Supporting the Marines.") The strong point fortifications “were to serve as both patrol and fire support bases. On-call, preplanned artillery fires were to cover the entire area, and tactical aircraft were to be available on short notice for support.” All non-combatants would be removed and relocated. Reaction forces would be stationed a short distance to the rear, ready to quickly deploy as needed. Construction of the strong points was nasty work, made more difficult and dangerous by an increasing volume of fire from within and across the DMZ.
The NVA gunners knew precisely where their immobile targets were; to return fire the marines had to search the foggy, forested hills to the north. Taking a page from his Dien Bien Phu playbook, the enemy hid artillery in the mouths of caves, rolled out the pieces to fire a quick volley, then jerked the cannons back into the mountainside. The CO of the battalion at one of the outposts stated that his men “much preferred to take their chances on patrol than be sand bag fillers and bunker construction 'experts’ interrupted by incoming barrages.” The thoughts of an anonymous marine were more direct: “With these bastards, you'd have to build the zone all the way to India and it would take the whole Marine Corps and half the Army to guard it; even then they'd probably burrow under it.”