Originally posted by Lord Lucien
[B]They'd be harder hit if the invasion was pre-RotS, but I have a hard time believing that this galaxy-sized industry of magical, wondiferous technology, and millions of worlds wouldn't be able to ramp production of everything military to its zenith in an incredibly short amount of time. It didn't take long in to the Clone Wars for the Republic to spit out countless capital ships, cruisers, frigates, fighters, and materiel, and that's with a huge chunk of their industry out of action and fighting against them.
Yes, but even at the start of the CW, both sides had an actual army and had army-production factories working and churning out complete forces. The initial clone wave was there to hold things off while more was made- and there was the matter that *neither* side was good at large-scale war at first.
If the Vong attacked during Phantom Menace, the factories to make droid armies and labs to make clones wouldn't be ready to start work off the bat, they'd have to be assembled first.
The early days of such a war would be very bloody, with only small local defense forces to face them. They'll likely eventually turn it around, but it's possible you'd see most of the galaxy fall and things turning into a much, much longer conflict as the Vong take early opposition piecemeal, and reach more of the production centers to destroy them, and result in a situation akin to the New Sith Wars where both sides production capabilities drop as the conflict drags on.
The Vong are never going to take the whole galaxy in later eras, but they could quite possibly inflict something akin to the Republic Dark Ages all over again.
Veterans will be produced very, very quickly. And unlike pre-existing vets who would be conditioned to fight a certain way, here you have a generation of greens getting all their experience from fighting one enemy. There'll be no Charge of the Light Brigade blunders here.
There will be blunders like the arena at Geonosis that cost so many Jedi. It took awhile for the Clone Wars sides to relearn a lot of the aspects of war. And you're likely to see a lot of the early forces sent against them wiped out completely however well they fight.
Late-CW would adjust to the Vong fine, but 10 years prior they'd have to make those mistakes against a much larger more dangerous force than the droids, and there'll be a tough decision between 'sending in forces when they're ready' and 'holding back until you've got enough to do a lot.'
In NJO, even once everyone was up and responding, the strategists used small delaying actions in order to buy time to build up a more sizable force to put in the most important areas in order to maximize effect. It was bad for morale, but made strategic sense. Pre-CW admirals won't have a lot of experience and they may waste more forces not realizing how to fight with such a large scale in mind.