I would say "end of chat control, for now"

Those guys only ever have a "maybe later" button.

That's pretty much how it works; there's generally no way, in a modern parliamentary democracy to say "no, and also you can never discuss it again". You could put it in the constitution, but honestly there's a decent argument that parts of chat control would violate the EU's can't-believe-it's-not-a-constitution (the Lisbon Treaty is essentially a constitution, but is not referred to as such because it annoys nationalists) in any case and ultimately be struck down by the ECJ, like the Data Retention Directive was.

Constituional cours are a last defense against bad laws though and should not be the first one - they are not designed to be fast enough to prevent a lot of damage being done before they strike something down.