Today, an ordinary person can't pick up the phone, email a friend or order a book without comprehensive records of their activities being created, archived, and analysed by people with the authority to put you in jail or worse. I know: I sat at that desk. I typed in the names.
When we know we're being watched, we impose restraints on our behaviour – even clearly innocent activities – just as surely as if we were ordered to do so. The mass surveillance systems of today, systems that pre-emptively automate the indiscriminate seizure of private records, constitute a sort of surveillance time-machine – a machine that simply cannot operate without violating our liberty on the broadest scale. And it permits governments to go back and scrutinise every decision you've ever made, every friend you've ever spoken to, and derive suspicion from an innocent life. Even a well-intentioned mistake can turn a life upside down.
To preserve our free societies, we have to defend not just against distant enemies, but against dangerous policies at home. If we allow scarce resources to be squandered on surveillance programmes that violate the very rights they purport to defend, we haven't protected our liberty at all: we have paid to lose it.
Edward Snowden is a former NSA contractor and whistleblower