US will surely impose tough sanctions on China, which would be much more disastrous to them than the sanctions US imposed on Russia after Crimea.
EU will likely join in.
What will China actually gain from this? Not much besides scoring some political gains at home which they don't need anyway.
China views Taiwan as inexorably part of their homeland. The existence of a 'separate Taiwan' is kind of like a permanent stain to them.
Imagine if during major American political upheaval, Texas became it's own state again, and after takeover by Central/South American political entities, decided not to rejoin the rest of the US as the political situation stabilized.
Americans wouldn't rest until they reclaimed it.
I'm not justifying it and personally I would have liked to have seen a 'Chinese Federation' i.e. Hong Kong, Taiwan, mainland China, possibly even Manchuria as separate entities, possibly with 'Tibet' as managed-but-autonomous region. Instead of a single autocracy.
Doubtful. The EU, and France in particular, has been selling China weapons for over a decade.
Like all politicians, domestic policies are usually harder to gain political points vs foreign policies. It is also much harder to fix when problems arise. This is why head of states like the US president have traditionally spent more time on foreign policy. All leaders think about their legacy. If Xi can reclaim Taiwan, he will be remembered for decades. That is powerful motivation for any leader, especially one that is elderly.
The US is currently run by a lunatic. Are you so sure Trump would impose sanctions? Most of his decisions are made in a fit of rage, rather than thoughtful thinking. The fact he met with Kim, should tell you something about his decision making. The problem is Americans has played this big brother role for the last 50 years, but now there is a potential contender on the playground. I am not sure the US can do much here considering China is cash rich to withstand any sanctions you impose on them. China can use Trumps playbook too if they wanted like subsidising farmers, but they haven’t cause they don’t need to.
I suggest you look up US deployments and see why Taiwan while is of a huge cultural, political and ideological significance isn’t that much of a strategic significance in a conflict there are a lot of assets in theater already and the US while being a military backer of Taiwan limits its presence and support in order to never make them significant enough to justify an invasion.
Nobody is thinking that the US is going to attack the Chinese mainland.