We owe a lot to Edward Snowden, the former CIA employee who has exposed large-scale surveillance efforts in the US and worldwide. He has accomplished what the US Congress could not and the federal courts have refused to do. Far from committing an act of treason, as some have suggested, by all appearances he's done a public service.
Thanks to him, we now know about the secret court order compelling the telecoms company Verizon to disclose to the National Security Agency (NSA) information on all phone calls it handles. We also now know about the secret NSA programme Prism, which allows access to information in the servers of Microsoft, Yahoo, Google, Facebook, YouTube, Skype and Apple, among others. And we know more about the ways the NSA is able, through its "Boundless Informant" initiative, to collate the information it mines.
These disclosures reveal two trends in the US approach to intelligence - starting with the Bush administration, and augmented on President Barack Obama's watch.
First, when given the option of broad surveillance powers at home and abroad, US intelligence agencies have pushed it as far as possible. Why be constrained by the quaint concepts of following individual leads and demonstrating probable cause when they can instead sift through millions of telephone logs and plug directly into the servers of the e-mail and social networking platforms?
Second is the trend of state secrecy gone mad. The sweeping collection of phone "metadata" records was made possible by amendments in 2008 to the Foreign Intelligence Surveillance Act, which exempted such surveillance from oversight.
Thus, the government has no obligation to reveal whose communications it intends to monitor, and the Foreign Intelligence Surveillance Court, established by the act, has no role in reviewing how the government is using the information. Remarkably, even if the court finds the government's procedures deficient, the government can disregard those findings and continue surveillance while it appeals against the court's decision.
The American Civil Liberties Union challenged the law's constitutionality on behalf of Amnesty International, human rights lawyers, and other organisations. Dismissing the case last year, the US Supreme Court said that the groups couldn't show they were likely to be subject to surveillance. And how could we? Surveillance and the court orders that authorise it are secret.
Obama said last week that congressional oversight is the best guarantee that Americans aren't being spied on. As for the rest of the world, well, we've been on notice for some time that we're fair game.
US prosecutors are said to have identified dozens of possible charges against Snowden that are also crimes in Hong Kong, a requirement of securing extradition. The charges will probably include violations of the Espionage Act, which appears to offer no possibility of a public-interest defence.
It would be a miscarriage of justice if Snowden isn't allowed to put forward such a defence. He has said he reviewed the documents to ensure he wasn't putting anyone at risk. And there's no question that the programmes he exposed are matters of public interest.
If Hong Kong receives a request for Snowden's extradition, it should insist not only that the charges have equivalents in domestic law but also that the public-interest defence is available upon extradition. If it's not, the request should be refused.
Michael Bochenek is Amnesty International's director of law and policy