In brief, they fought over a hill of beans and, in the end, they unleashed the very weapons of mass destruction which everyone feared one day the "terraists" might use against a major city.
But, instead of a single city, which would have been terrible enough, the fools engaged in what they considered to be a "minor exchange" of a mere 50 or 60 nuclear devices. The result was a pall, a dark shroud of blackening sky which enveloped that poor world.
One of the unknown poets of the Third Galaxy, probably the same as coined the phrase, "All the bombs are in the hands of terrorists", wrote the following poem about what was obviously going to happen:
Approximately four years from today,
The skies above will no longer be blue.
There will be a darkening, blackening gray
Which will hide the sun and his rainbow hues.
It's then we will ask, "What was the cause?"
"Why did we fight over a hill of beans,
Violate our own and Nature's laws,
Committing such acts insane and obscene?"
"Cain killed Abel, but we did much worse,
For we have destroyed our Mother, the Earth!"
There was a wise man, who long ago said,
That the living would envy the dead
And now we must learn exactly what he meant.
When the Alien Veggies appeared in the blackened skies of the Third Galaxy in their strange ships of Cucumber, Pineapple, Eggplant and Hokkaido and all the rest, they cleansed the blackened skies of the Third Galaxy and saved them from the suffocating death of nuclear winter.
(You can see an animation of what it would look like from space as the Veggies would see it.)
However, we should not expect or even dream of such a reprise from our well-earned demise. The chances are less than zero for those who live in this, the real world.