The study assumes that China would strike first and strike hard to give us a bloody nose so stunning that we won't intervene or won't intervene with enough in time to prevent China from achieving their objectives.
Personally, I've felt that the Chinese would move on Taiwan only, while placing their forces between Taiwan and our forces in order to make us worry about being attacked by Chinese forces. See this September 2005 post that reacts to RAND testimony to Congress in what sure sounds like the early version of the 2007 study cited above. The Chinese objective would be to slow us down, I figured. Given that the Chinese would argue that the China-Taiwan fight is an internal matter, I judged the Chinese wouldn't attack us or Japan and make it an inter-state fight. It would make it easier for us to intervene if China attacks us or Japan, but if China strikes Taiwan while avoiding an attack on anybody but the Taiwanese, that would allow Americans opposed to fighting China to argue it is just an internal matter.
The RAND study notes that China pledges not to strike first even as they assume they must strike us first to nullify our military advantages. The resolution of this dilemma is solved by China's definition of an enemy "first strike:"
This paradox is explained by defining the enemy’s first strike as any “military activities conducted by the enemy aimed at breaking up China territorially and violating its sovereignty” (Lu, 1996). By this definition, any U.S. military support or deployment to address a military crisis around Taiwan could be interpreted as a “military activity aimed at breaking up China” and thereby rendered the equivalent of a “strategic first shot.” This could serve as sufficient pretext for China to launch a military strike against U.S. forces (Lu, 1996).
War could break out in the no-man's land between China's assumptions and ours. Deep down, we view Taiwan as in independent democracy. We could easily start shipping in ammunition and weapons to Taiwan in the early days of a war while we refrain from shooting as we deploy more forces to the region. We would see this as activities short of war. We could tell ourselves the Chinese will see our resolve and back down.
The problem is the Chinese will see this as a first strike on themselves and they may react by shooting at our still-deploying forces.
This is only one of the problems of trying to assume that we can limit a war by signalling each other during a fight. And this is a problem for the first minutes of war. Imagine the difficulty of reading the other side after we've been shooting at each other and after we've suffered casualties.
We can't afford to let China conquer a free Taiwan. So as long as China claims Taiwan we have to push Taiwan to arm themselves and be prepared to beat China in a war over Taiwan. But it would be better if we could bend events so that either Chinas doesn't want to absorb Taiwan or China is unable to focus on Taiwan.
China thinks they can fight a nice limited war against our forces. I wouldn't bet on that assumption. We're not even speaking the same language.