But that misses the point. The politicians are not arguing for a world where nobody can encrypt. They want strong encryption which can only be opened by two groups: the intended recipient, and the authorities.

We know that such a system will inevitably lead to other groups also gaining the ability. Rich criminals, security services all around the globe (friendlies and the enemies too). Either by bribing, or impersonating authority figures or by stealing the backdoor keys. What is at dispute with the politicians is the probability of this happening.

How would a service voluntarily leaking the private information of politicians convince them that we cannot build a backdoor into encryption without that backdoor proliferating widely?