Priscilla Alvarez: To start, what is an intelligence-sharing arrangement?

James Igoe Walsh: It’s when one country has intelligence that it gives to another country—that’s the basic part of it. Typically, the receiving country is going to promise not to share that [information] onward to other countries without permission.

More generally, these intelligence-sharing relationships are usually embedded in a larger bilateral relationship, which might involve alliances, military cooperation, economic cooperation, and stuff like that. It’s important to see them as part of that larger relationship as well, because it might mitigate some of the consequences when things like this happen.

Alvarez: Can you elaborate on how that larger relationship might mitigate consequences?

Walsh: We don’t know the country that shared this intelligence. We have to think about: What is that country’s interest in sharing it? They probably want to have some sort of influence over U.S. policy. Maybe not with this specific piece of intelligence, but more generally. And they may also want to secure something in return—at least implicitly—from the United States, like military aid. That country might look at this as a sort of betrayal of their intelligence-sharing agreement, which would be bad, but they may also balance that against their other interests in their overall relationship with the United States.

Alvarez: In your book, you note that there is always room for doubt in these arrangements. The providers of intelligence can’t be sure that it’ll be adequately protected. Is intelligence sharing, then, based on trust?

Walsh: No. Trust is really important, because if you can’t trust your partners not to treat the intelligence you share in some secure way, then that’s a real major cost for the sharing or the sending state. But like in other parts of social life, we can build institutions that supplement trust. In our daily lives, we might have a lease with our landlord that is, in part, based on trust, but ultimately it will be backed up by a written contract. You can’t really do that in international relations because there are no real courts, but there are ways you can structure the relationship so that each side can monitor the other more closely.

For example, often the United States provides a lot of technical assistance to its partners so that they can use technology to collect and analyze intelligence. And that’s going to improve the efficiency of the partner country’s intelligence agency, presumably. But it also might give the United States some insight on what that country is actually doing on the ground, and that might give some insight into how valuable their information is or how trustworthy it is.

Alvarez: Is a president sharing information from another source voluntarily—and without permission—with another country unprecedented?