His security-liberty quote. It's easy to frame this as "trading the liberty of free speech and free association for the security of being free from Chinese propaganda," and I agree that we should be discussing the validity of that framing as fervently as we possibly can because at the face of it, it appears to be exactly that. Every argument against that framing seems to be trying to carve out an exception for the purpose of security, often with extreme language of existential threat.
I don't see why anyone would argue on security. They keep American social networks and software products out unless they "partner" with a Chinese company. It seems obvious we shouldn't allow a double standard here.
We gave up on forcing China to keep opening up to US trade if they want us to reciprocate. We shouldn't do that.