Surveillance of communications of private chats is never okay. Law enforcement can access chats via device directly from the arrested person if necessary. Backdoors via service providers is bad idea. Democratic countries, you know the so called "government rule of the people" doing this or pushing for this is deeply anti-democratic. Non-democratic countries and monarchies obviously has fickle laws that can change at any moment and one cannot expect "democracy" from them. For me democracy means inclusive of all citizens, considerate of every citizen and citizens not having to worry about sneaky laws trampling upon privacy or rights. Democratic governments making mass surveillance laws or making deals with foreign governments to side step constitutional rights and privacy is wrong on a different order of magnitude. Providing security for nation doesn't require mass surveillance. Decent physical non-overreaching policing on the ground is all that is necessary for decent acceptable level of security.