They can’t. They don’t have transportation capacity for a amphibious operation of that size, nor, most importantly, can they establish air superiority over the straights even without US Carriers enjoining the battle.
All that would do at this point is result in massive humiliation and defeat. They’re FAR more likely to go adventuring somewhere landwise. Siberia... even India perhaps.
I don’t think the ChiComms would quite do it that way.
Their battle plan would call for a missile attack (purchased from Russia) and air attack to cripple Taiwan’s air force. Then the ChiComms would deploy their fleet of diesel-powered submarines (purchased from Russia) to enforce a naval blockade against Taiwan. Upon execution of this plan the ChiComms would present a political ultimatum to Taiwan: submit or be economically strangled.
At this point we would face only bad choices. To deploy our aircraft carriers in these waters would expose them to devastating missile and submarine counterattacks. The only viable option would be to enforce a counter naval blockade against China in the Straits of Malacca .
If John McCain were President I believe the counter blockade strategy would have deterred the Chinese because he would order it. With Obama in charge I would only expect feckless protests at the U.N.