Mark Kleiman rebuts an argument of mine:
Eric Posner says that since the other parties to the Convention Against Torture are unlikely to do anything to enforce its provisions, Holder has full discretion to decline prosecution on political or policy grounds. But a duly ratified treaty is the law of the land, and Holder is sworn to uphold the law. Could he get away with not prosecuting, in the face of enough evidence to convict? Sure. But he'd be violating his oath of office.
Andrew Sullivan chimes in: "And unlike under the Bush administration, that is no longer actively encouraged."
There are two problems with this argument. First, if my premise is accepted, that a treaty obligation ceases to have binding force when other states fail to comply with it, then neither the attorney general nor the president would violate his oath of office to uphold the law by failing to respect that treaty obligation. One might contest my premise, of course; but Kleiman does not.
Second (and more interesting), Kleiman's argument rests on doubtful premises about American law. "Oath of office" arguments are derivative: they implicitly make claims about what the Constitution means. Here, Kleiman advances a syllogism, which I would reinterpret as follows: treaties are "the law of the land," the president has the duty to "take care" that the law be executed, therefore, the president has a duty to take care that treaties be enforced. This is, at best, a controversial interpretation of the law.
For 200 years, the supreme court has recognized a distinction between "self-executing" treaties and "non-self-executing" treaties. Self-executing treaties have the force of domestic law; non-self-executing treaties do not. The Convention Against Torture is a non-self-executing treaty, according to a Senate reservation. The president and the Senate chose to incorporate the treaty through domestic law, and Congress duly enacted the anti-torture statute. That statute incorporates, in modified form, the CAT's ban on torture but does not incorporate section 7, and thus does not try to constrain prosecutorial discretion (and it is not clear that it could).
Section 7 of the Convention Against Torture thus is not judicially enforceable. Could it not still be a "law" that binds the president? It could be; no court has resolved this question, no doubt because the question could never appear before a court in the first place. However, there are strong reasons for doubting that the president, and hence, the attorney general, have any constitutional obligation to "take care" that a non-self-executing treaty be enforced. It is a generally accepted proposition in foreign relations law that the president has the authority to terminate international treaties. President Carter did just that when he terminated a treaty with Taiwan, an act that led to a famous Supreme Court non-decision in 1979 that left his act undisturbed. Such a power cannot be reconciled with a constitutional obligation to take care that treaty obligations be enforced. Presidents also violate treaties. Consider President Clinton's military intervention in Serbia in 1999, in violation of the UN Charter. Treaty violations at the orders of the president—and the U.S. has a long history of them—also cannot be reconciled with a constitutional obligation to take care that treaty obligations be enforced. Perhaps one might argue that President Carter and President Clinton violated their constitutional duties and hence their oaths as well, as did many of their predecessors and successors. But given the long history of presidential discretion in this area, it is a bit late to make this argument.