Answer:
Damage America's morale, damage US international image in the international community, and guerrillas for extending the conflict
Step-by-step explanation:
North Vietnam inflicted sufficient casualties on the American side as to damage the army's morale. Since America was seen also as a colonialist empire people was willing to sacrifice everything in the war effort, to expel the invaders. ´While the conflict overlasted the US troops, the support for the war back at home and in the public view was fiercly pressing the US retreat.
Vietnamese sought to keep the American combat forces busy in the hinterlands, far away from the people in the villages who were continously providing sustainment to military and political forces of the revolution.
The North sucessfully lead ultimately the Revolution to establish the communist rule and became and independent nation thereafter.