[expatpat]

Rather than talk about the South Vietnamese Army's lack of heart, Americans expressed awe of the Viet Cong guerrillas operating in South Vietnam, who never quit. People tended to interpret the VC's relentless will to fight as being based on their absolute belief in communism. I think, however, that the VC were simply stone killers who believed in nothing in particular, but that totalitarianism – any brand will do – encourages those in power to be conscienceless stone-killers.

I think the VC were motivated by the fact that they were to a large extent fighting for their homeland. People, and animals, will fight much more intensely for their own territory than for other things.

[mrustow]

But the South Vietnamese soldiers were also fighting for their homeland.

[aristeides]

I think the VC were motivated by the fact that they were to a large extent fighting for their homeland. People, and animals, will fight much more intensely for their own territory than for other things.

Doesn't guarantee victory, depending on the circumstances. South lost the Civil War. English conquered Ireland (for 900 years or so) and Wales (permanently, at least up to now). Many other counterexamples.