Daniel Davies is rather more elated than Will Baude at the failure to prosecute GCHQ leaker Katharine Gun; apropos of the same topic (though he doesn’t acknowledge it explicitly), John Quiggin suggests signals-intelligence doesn’t work in game theoretic terms.

Turning first to Quiggin, it’s generally my (probably ignorant) observation about game theory that it’s infinitely malleable, and thus of limited value. I assert process X is governed by game Y; you assert it is governed by game Z. Some examples show Y is better, some show Z is better. As a way to categorize situations in retrospect, games work fairly well, but they usually aren’t a very good template for figuring out how future situations will play out.

As for the Davies-Baude debate, I think it’s useful to start from the facts. Gun engaged in illegal conduct in revealing that the British government may (or may not) have been cooperating with the American government in doing something—namely spying on diplomatic missions—that may (or may not) be illegal in either or both countries. To the extent there are laws against spying on diplomats, I suspect they aren’t widely followed; that it was a major breach of diplomatic protocol for the Soviets to spy on the United States didn’t stop them from filling the never used “new embassy” in Moscow with listening devices.

To the wider question: should spying on other countries, and their citizens, be illegal? There are good reasons for governments to not be allowed to spy on their own citizens and permanent residents. Many do it anyway, mind you, but most democratic countries tend not to. And there are good reasons why governments shouldn’t be allowed to receive intelligence about their own countries collected by third-party governments; look no further than the Maher Arar case, where it is fairly clear that elements of the Canadian government tried to get the U.S. and Syria to do their dirty work for them. On the other hand, if the Chinese want to spy on me, there isn’t much actual harm to me, given that the Chinese don’t have any legal authority over me.

So what should the libertarian position on non-domestic espionage be, in a non-ideal world where other countries have no compunction about spying on other societies?