President Obama is considering reforms for intelligence gathering to protect the rights of foreigners. Those outside the American intelligence community may not realize this, but this is a major conceptual leap. Previous efforts to reform surveillance activities have always been about limiting spying on Americans.

There are reasons for strict rules on domestic spying. Spying on your own citizens is poison in a democracy, because the party in power can misuse it for its own ends. Nixon's betrayal of trust began with a break-in by former spies at his opposing campaign's headquarters. No president has ever faced a similar backlash because he spied on foreigners, and Obama is hardly likely to be the first.

For these reasons, intelligence oversight has traditionally been about the rights of "US persons" – citizens and legal permanent residents – in order to guard against improper domestic spying. Still, while providing limits on foreign spying may seem revolutionary, the policy shift would be less drastic than it appears at first.

There are ways President Obama might more formally protect the rights of foreigners that the US intelligence community could find workable. First, the law already requires all intelligence activities, including those directed at foreigners, to serve a valid national security purpose: NSA may collect only "information to respond to intelligence priorities set by the president". These priorities are embodied in the National Intelligence Priorities Framework (NIPF), set annually by the president through an interagency process. The NIPF is classified, but in essence it tells the intelligence community what is important to national security. If a collection operation is not geared toward one of those requirements, it is not authorized – even if it is directed exclusively against foreigners.

This is not a hypothetical safeguard. Over the past decade, the NSA's internal oversight – while directed primarily at enforcing rules against spying on Americans – has uncovered a very small number of intentional violations involving foreigners. They included something that became known inside the NSA as "LoveInt" – misuse of NSA's apparatus to track foreign subjects of romantic interest. Even though the subjects were not US persons, the perpetrators were disciplined. The activities had no legitimate national security purpose and were certainly not responsive to the president's intelligence priorities.

So the US already has a system of intelligence oversight that has the effect of providing some protection for foreigners, even if we do not think of the system as having this purpose. Why shouldn't this rule – one that forbids intelligence activities that infringe the privacy of foreigners for no valid national security purpose – be more clearly formalized? It would not limit any legitimate intelligence activities; nor would it require any new compliance requirements. However, it would give the large majority of the world's citizens who are not "US persons" a sign that their privacy is of some formal value to the United States.

A more difficult question is whether to constrain the ability of the United States to set its intelligence priorities unilaterally. Broad international consensus favors collection for the purpose of preventing international terrorism and proliferation of weapons of mass destruction. Other topics, such as spying on foreign militaries, might be seen as fair game. However, consensus would break down quickly. The US objects to China's economic espionage, for example, while Brazil and Germany are up in arms about US spying on their leaders. It is clear that global consensus could never be reached on the proper scope of intelligence collection.

The US and its closest allies, including the United Kingdom, already informally agree to very strict limits on spying on each other's citizens. A larger group of democratic nations might agree to limit spying to a narrow group of topics – excluding commercial espionage and political spying while permitting spying on topics of real security interest.

Such an agreement might be hard to achieve, even among like-minded nations. As a first step, President Obama should make clear that spying on foreigners is not without limit. Violations of those limits are already punished through the intelligence oversight system. Making clear that intelligence oversight is not focused only on protecting the rights of Americans would not degrade intelligence collection. Privacy is a basic human value and a basic human right, and it should not be limited to Americans.