It’s easy to see how an inability to keep secrets can hamper diplomacy. But it’s also worth considering the ways in which the ability to keep secrets can hinder diplomacy. Consider Iran. Suppose Ayatollah Khameini has a spiritual awakening and decides he doesn’t want nuclear weapons. But he thinks that for Iran to sign away its rights under the Non-Proliferation Treaty would be a national humiliation too far. Why should Iran be treated any differently than Germany or South Korea?
Obviously it would be in the interests of the West to strike a bargain around these terms. But equally obviously, if the Iranian government were to propose these terms there’d immediately be a problem of credibility. The West would insist on credible, verifiable disarmament which is a different thing and might require steps that Iran won’t agree to. In part, inability to strike this bargain is part of the price Iran needs to pay for past bad acts. But in part it’s a price Iran is paying precisely because Iran can keep secrets. If WikiLeaks were constantly publishing Iranian diplomatic cables, it would in some ways be easier to do a bargain. Or on the flipside you sometimes hear that the United States can or should offer “security guarantees” as part of a deal. Actual guarantees from the US should be quite valuable. But talk is cheap. And the fact that we’re able to keep secrets tends to turn our potentially valuable guarantees into cheap talk.
Indeed, as John Ikenberry has written in some ways it’s the degraded secrecy capabilities of democracies that makes it possible for us to collaborate so intensively. One reason the peaceful US/Canadian relationship works is that clearly in practice there’d be no way to mobilize the country for an invasion without it leaking. The fact that there are no such leaks gives the Canadians confidence that we’re not secretly planning to invade, which means they don’t spend their time plotting for an asymmetric war with the United States. And since they’re not doing that, we’re not constantly worried about Canadian terrorist financing and WMD programs and drawing up plans to invade.