My sub-point is America would deny the validity of China's invasion of Taiwan regardless of whether China's accusations against Taiwan were accurate or not, meaning the accuracy of such accusations isn't relevant. The outcome is the same. People in the EU might roll their eyes and say "ackshully china is right and taiwan really is making nuclear weapons", just as they once rolled their eyes at America's bogus claims about Iraq, but what would/did that change? A fat lot of nothing.

But my main point is that if Taiwan wants nuclear weapons they can make their own, so there is no sense in America giving nuclear weapons to Taiwan. And if America did, that would provide China with 'valid' casus belli anyway. I think PRC spies would be no less aware of plans to import nuclear weapons than plans to make them.