The intelligence was fascinating. The 324th Division of the North Vietnamese army had crossed the border, it said, and had massed in Quang Tri province next to the 17th parallel's demilitarized zone. It was the first full division ever reported to have come down, it numbered 8,000-10,000 men, and its apparent mission was to deliver a sudden and overwhelming attack upon the two northernmost provinces of South Viet Nam, including the old imperial city of Hué.
To counter the plan, General William Westmoreland ordered a massive spoiling operation. It was called Operation Hastings, and it involved nine battalions of U.S. Marines, the...