The focus on bulk collection of metadata is based on the assumption that it can be used to stop terrorists and other enemies. This assumption remains unproven. American drones routinely murder people abroad purely because of their metadata, and yet peace is nowhere nearer.

At home, it turns out that it is pretty much impossible to stop a handful of people who have access to weapons, want to do as much damage as possible, and don't fear death. Increasing the surveillance on regular citizens will not change that.