> Surveillance being illegal protects us from it being used against us in legal proceedings. Even if we can't prevent spies from spying, at least we don't have

> Surveillance being illegal protects us from it being used against us in legal proceedings. Even if we can't prevent spies from spying, at least we don't have to worry about the evidence they collect being used in court. That is an argument to make surveillance legal. If the illegal surveillance is indeed useful in court proceedings to prosecute other illegal actions, then it makes sense to make the surveillance legal so that the true criminals can be brought to justice. The legal principles of appropriate measures should still apply - surveillance should not be used to prove jaywalking but rather be used to combat more serious crimes. Appropriate use of surveillance should be legal. The problem with illegal surveillance is when it is used to record legal behaviour and control citizens behaving legally but perhaps indecent. Such as recording amoral behaviour of political dissidents or political opposition and later releasing it to the press to gain politically. Gathering evidence of homosexuality of a priest or union leader could be another example, and use this surveillance to stop the union leader from becoming a problem for the political power. Also, surveillance used today can be used by a future power for nefarious purposes. Imagine that Hitler would have been able to access 10 years of video recordings of synagogues, which may have been originally recorded for the purpose of protecting the synagogues from attacks. The recordings can be used for something else entirely in the future. Surveillance in general is a very powerful weapon and should be treated like all powerful weapons - with respect and very carefully.