They attacked only at night under the cover of darkness. Their tactic was to engage in small skirmishes in the South Vietnamese countryside where they were familiar with the area. They used guerilla warfare and had their trip wires and pits with sharpened bamboo stakes to demobilize the enemy. After the battle, they escaped back to the jungle.
This is of course impossible to tell, but most agree that if the Articles of Confederation hadn't been replaced by the more powerful Constitution, the federal government wouldn't have had the power to tax the states and therefore wouldn't have been able to re-pay its war debt--causing the new nation to crumble.
The answer is (A) Reincarnation