Things will get wild for TW anyway, and it's better to concentrate semi in East Asia which incentivizes US to commit future security. It's less effective silicon shield than fabs in TW proper, but not as suicidal as setting up plants in Arizona. And at end of the day, JP / US / EU is using as much sticks as carrots to wrestle fabs out of TSMC outside of TW soil. There's too much dependencies for TW to say no.