[int_19h]

The governments always could do that, but then they'd be the target of the pushback, and there's already significant mistrust of governments wrt surveillance because of how it can be abused.

What we have now is Apple, with its "strong privacy" record, normalizing this. If it succeeds, it would be that much easier for the governments to tackle other stuff onto it. Or, say, lower the threshold needed to submit images for review. I can easily picture some senator ranting about how unacceptable it is that somebody with only 20 CSAM photos won't be flagged, and won't somebody please think of the children?

And yes, if it comes to that, Apple definitely cannot hold the line. After all, they already didn't hold it on encrypted cloud storage - and that wasn't even legally forced on them, merely "not recommended".