By Mike Dorf (substantially amended in response to a comment)
The diplomatic impasse between the U.S. and Pakistan boiled over with the breaking of the story that Raymond Davis, the American being held by Pakistani authorities on murder charges, was in the employ of the CIA. Davis has been classified by the U.S. as "administrative and technical staff" but he is part of a task force that monitors (and takes or facilitates covert action against) militant groups in Pakistan. Several weeks ago, Davis shot and killed two Pakistanis who, he says, were attempting to rob him. Accounts of the exact circumstances differ, but there is agreement that after the shooting, another U.S.-based vehicle killed a Pakistani pedestrian while its driver was attempting to come to Davis's aid, i.e., presumably trying to whisk Davis away before the authorities arrived. The rescue effort failed and Davis was arrested. The U.S. has strenuously insisted that Davis is entitled to diplomatic immunity. Thus far, the Pakistani government has resisted calls for turning Davis over to the U.S. The case has caused a further deterioration of the already-frayed relationship between the U.S. and Pakistan, and angered many people in Pakistan who were already upset about U.S. policies like drone attacks on suspected militants.
What's the right legal analysis? That may depend on what treaty applies. Article 41 of the Vienna Convention on Consular Relations provides that "[c]onsular officers shall not be liable to arrest or detention pending trial, except in the case of a grave crime and pursuant to a decision by the competent judicial authority." There may be borderline cases that raise the question of what constitutes a "grave crime," but certainly murder counts as one. Of course, Davis could well have acted in self-defense, but under the treaty, if that's so, Pakistan is entitled to make his self-defense argument subject to adjudication in its courts.
Notwithstanding Article 41, Davis could perhaps be immune to prosecution under Article 43. It provides: "Consular officers and consular employees shall not be amenable to the jurisdiction of the judicial or administrative authorities of the receiving State in respect of acts performed in the exercise of consular functions." The problem here is that Davis does not appear to have been engaged in any consular functions. He was engaged in intelligence operations while acting under cover of a diplomatic passport. Or so it appears anyway. Perhaps the U.S. has an argument that in fact Davis had a genuine consular position of providing security services for U.S. diplomats. But the U.S. has not said anything like that publicly.
Another possibility is that the U.S. takes the position that the receiving nation must accept the sending nation's assertion that one of its nationals was engaged in the exercise of consular functions when arrested, and thus immune. But this is a hard sell also. For one thing, I haven't seen that the U.S. has made this claim. For another, there is nothing in the text of the treaty that supports it. And finally, I am nearly certain that we would reject such a claim if the shoe were on the other foot. Suppose that during the Cold War a suspected KGB agent killed two Americans. Would we simply have accepted the Soviet assertion that he was really engaged in performing some consular function? Even if we ultimately released him to the Russians, that surely would have been the result of a political negotiation, rather than out of a sense of legal obligation.
But perhaps instead of the Vienna Convention on Consular Relations, the case is governed by Article 31 of the Vienna Convention on Diplomatic Relations, which provides: "A diplomatic agent shall enjoy immunity from the criminal jurisdiction of the receiving State." Davis isn't a diplomatic agent, but Article 37(2) extends the immunity of Article 31 to "[m]embers of the administrative and technical staff of the mission." Here too, though, the U.S. position looks shaky if Davis isn't really part of the administrative or technical staff but is simply using that as a cover. Once again, the U.S. might avoid that result if its designation of its staff were given conclusive weight, but it is not obvious that things work that way under the treaty. Consequently, the bottom line is that Pakistan's legal position may be stronger than it has been portrayed in the U.S. media.
Finally, I should be clear that Davis may well be guilty of nothing more than having had the bad fortune to be robbed and having defended himself. It's also quite possible that a trial in Pakistan would be unfair to him. Thus, I have nothing against diplomatic efforts to secure his return. That, however, is something quite different from the position that the Administration has repeatedly taken--that Pakistan has an obligation under international law to release him.