> National security and public safety IS more important than individual right to privacy.
I disagree.
Because as soon as you open the door to governments reading your mail, they will read your mail. They can't help themselves. [0]
The only way of stopping them from doing this to excess is to stop them doing it at all.
The "National Security and Public Safety" thing is what they say to justify it, but that's not what the powers will actually be used for. They will actually be used for far less noble purposes, and possibly actually for evil.
We are actually much more secure if we don't let the government read our mail.
[0] In the UK, anti-terrorist laws passed in the post-9/11 haze of "national security and public safety" are routinely used for really, really, minor offences: https://www.dailyrecord.co.uk/news/scottish-news/anti-terror...