In particular, if you use Proton Mail, a hostile government wants to surveil your email, and Proton Mail (with its quisling CEO) decides to oblige:
- They can still surveil everything sent to you by other parties.
- They can still surveil anything you compose in your preferred non-Proton email client (e.g. Mail app on your phone). [CORRECTION: They lock out such clients altogether on mobile, provide fiddly local relay for desktop]
- They can still backdoor their own product offerings (which is likely to go undetected without an open protocol with multiple clients).
- I suspect (but don't know) that their architecture that supports webmail also makes blanket surveillance possible.
6/