Edward Snowden has done us all a service by revealing how extensively our private communications are being monitored - not because of any targeted inquiry into criminality, but as part of a broad quest for intelligence.
The conversation he launched has already yielded some modest improvements in the protection of our privacy. But to understand how much more remains to be done, we must examine the rationales the US government uses to claim that its mass snooping is legal.
Given Australia's close intelligence partnership with the United States as part of the "Five Eyes" program (which also includes Britain, Canada, and New Zealand), we have reason to believe that Canberra applies similar logic.
First, Washington claims we have no privacy interest in the so-called metadata about our communications - the highly personal and revealing information about whom we call or email, what we search for on the web, which websites we browse, and even where we go physically (because our phones serve as electronic tracking devices).
The rationale? We are said to have waived our privacy when we "share" this information with a third party like a phone or internet company. Australia seems to have adopted a similar rationale, given the ease with which it lets many agencies gain access to this information.
The US Supreme Court endorsed a version of this view 35 years ago in a ruling about phone call data. It could just as easily have ruled that a communications company, like a doctor or lawyer in whom we confide, has a duty to preserve our confidence, but it didn't. Now, with electronic communications much more central to our lives and the capacity for government surveillance vastly enhanced, the court has hinted at misgivings about the "sharing" rationale.
That may be one reason why President Obama last week announced a new proposal to end the US government's bulk collection of phone data in the United States. But he has not recognised any limit on seizing metadata concerning our emails, web searches, and physical locations, or even admitted that we have a right to privacy in our metadata.
The bulk collection of metadata was put in place ostensibly to help prevent terrorist attacks, but the US government cannot identify a single terrorist plot that the program was essential for thwarting.
Second, the US government claims that our privacy is not affected when it collects our private communications, only when it reads, analyses, or listens to them.
This assertion has never been tested in a public court but was apparently approved by a secret intelligence court after hearing from only the government.
The one rationale the government offered publicly is the simplistic metaphor that one needs a haystack to find a needle - that the government must collect all of our communications data so it has the one piece that might reveal terrorist activity.
But that rationale makes a mockery of the requirement that the government can invade our privacy only upon an evidentiary showing that it is needed for a criminal investigation.
If the government's logic were played out, we would have no reason to object to the government even placing video cameras in our bedrooms with a direct feed to a government computer, so long as the government promised not to look at the videos until it had a good reason for doing so. Indeed, the cameras on our laptops and smartphones may already be playing that role.
Obama's latest reform suggestion, if Congress approves, would take the government out of the business of collecting Americans' phone data en masse, leaving that to phone companies.
Notably, given the difficulty of proving the worth of older phone data in comparison with the privacy intrusion, Obama would not, as has been proposed in Australia, require phone companies to retain data beyond their ordinary business practices.
But questions remain about the government's collection of other communications data and personal records. It is also unclear what evidence Congress will require for the government to access the data held by phone companies.
Third, even with respect to the contents of our communications (not simply the metadata), US law lets the government read your email or listen to your phone calls if you are outside the United States and not an American. That would include most readers of this article.
Washington arrives at that position by a cramped reading of international human rights law, claiming it has no duty to respect the right to privacy of non-Americans abroad. A UN rights committee challenged this claim last week, but the Obama administration shows no sign of budging.
Australians may feel that they are at least protected from snooping by their own government. But Australia has not admitted to any impediment against simply asking its Five Eyes partners for any private communication involving an Australian that it could not legally intercept directly.
These intrusions on our privacy evolved because we didn't know about them. In the United States they were overseen in secret by congressional committees and a special court without any public accountability. Many suspected them but we never knew for sure until Snowden opened this debate.
But there is now a danger of overreaction. Some are proposing to carve up the internet, requiring data to stay within a country as a way to avoid outside prying.
Even if that were possible, it could be a mistake, because many countries, such as China, have weaker protections for free expression and privacy than do the United States or Australia. Western internet companies know not to store data in China to make it harder for Beijing to identify and arrest critics. China would like nothing more than to be handed a rationale for requiring local storage of that data.
Rather, the answer to the excesses of mass snooping lies in strengthening the consensus around existing international privacy standards. Brazil and Germany have begun a process at the UN Human Rights Council to update our understanding of these standards in light of modern communications.
With that debate in public rather than behind closed doors, our right to privacy has a better chance of surviving the insatiable prying of intelligence agencies. Australia should support that effort, and push its ally in Washington to abide by the updated rules that emerge.