So. Who would win in a long, drawn-out, global war? Yeerks or humans? There are over six billion humans, not six million, six billion, and maybe, what, only a few hundred thousand Yeerks controlling a meager ten thousand plus hosts? Sure, they have advanced technology, but there are hundreds of millions upon hundreds of millions of humans, all with fair levels of technology, if not up to Andalite or even Yeerk standards.
I guess it depends on how it happened. The "open war" we saw in the last few books was disappointing to me. I imagined it happening VERY fast, lightning-fast strikes on major population centers, rounding up humans and their leaders to be infested, and quickly taking control in full view of the public. If they HAD done it that way, we'd be screwed. And really, that was the way Visser Three SHOULD have done it.
So, we're going to be creating a new fictional scenario.
If at the beginning of this hypothetical war humans learned immediately what was happening and were fully aware of their enemy's level of infiltration, they could better combat it. It also depends on if a good number of nations are allied. Will all NATO and western allies unite as one to fight the Yeerk threat? I think Yeerks impersonating the leaders of nations they want to take over wouldn't work as well as they think it might, because any military general or political leader acting even slightly out of character is going to be regarded with great suspicion.
And then there's the greatest advantage on our side: adaptability. If humans managed to capture or destroy a few Yeerk ships and secured some of the wreckage to study, they could create new technologies to fight the Yeerks by reverse engineering.
So, in the end, I think humans will win, but it will be a long, horribly bloody battle with massive casualties.
Oh, and I'm not even mentioning that as time goes on, the Yeerks would have to devote additional reinforcements to Earth to fight the humans, giving the Andalites time to push back (maybe even to form an alliance with the humans).
BTW how DO you create polls? Any help?