I had first arrived in South Vietnam in July of 1965. The US buildup had just begun. This much lower figure meant that the US army was now no longer in a position to launch, let alone maintain, a major offensive. The program of Vietnamisation was continuing. The regular Vietnamese army now carried the M16 rifle instead of the good if rather unwieldy old M1 Garrand. The US still had a large presence of advisers to the South Vietnamese army at all levels. I formed the opinion, that with the exception of the advisers, the Americans no longer seemed in a hurry to get killed and were more defensive than aggressive in their tactics.
The quality of the South Vietnamese army varied greatly. The Regional and Popular Forces fought very well when defending their home ground which was their job. The better units such as the Parachutists and Marines fought well as did some of the Ranger Units. There were not enough of these to be sacrificed uselessly.
I sometimes thought of the war as a game of chess. The South Vietnamese had the regular pieces. The queen being US air power. Their King being Saigon, former Pearl of the Orient and key to success or the North. The North Vietnamese only had pawns, but an unlimited supply of replacements. Their King (Hanoi) was off the board. It would be amusing to see a Garry Kasparov representing the South and some amateur the North. Such a much more fascinating game than the dominoes that the Americans seemed to favour.
The communists were fighting a war of attrition, trying to wear the South down on the battlefield, and the continuous assassination of officials at the local level. They also wore down American public opinion, helped of course by My Lai, Kent State, photos of the young napalmed girl etc. The US were unlucky in that they got a bad press. Of course they were the good guys, the boy scouts of the world an open to such charges.
The South Vietnamese and their American allies depended largely on US airpower to avoid defeat.
Such was the state of affairs when the communists launched their Spring offensive of 1972, four years after that of the Tet offensive of 1968.