Because of the Viet Cong's spying ability which precluded thorough planning, an inability by the political and military leaders of the U.S. and South Vietnam to face military realities and poor execution, Operation "Lam Son 719" collapsed when faced by the determined resistance of a skillful foe. The campaign demonstrated continued deficiencies in ARVN military leadership and that the best units of the ARVN could be defeated by the North Vietnamese, destroying the confidence that had been built up over the previous three years.