In regard to Tommy De Seno’s comments on my previous post about Tom Cotton’s letter, we should all recognize that there is a difference between the policy of any agreement with Iran and the constitutional law that governs the agreement. We can have different views about the best way to contain Iran’s nuclear ambitions without having to disagree on the constitutional foundations of sole executive agreements or a senator’s right to voice his or her personal views about the Constitution. For what it’s worth, one fix for the controversy would be for Senator Cotton to offer a resolution on the floor of the Senate opposing any nuclear deal with Iran that does not undergo advice and consent.

Some are criticizing the Cotton letter for attempting to interfere with the president’s “sole organ” authority to conduct the diplomacy of the nation. But I don’t think the president’s sole organ authority, first articulated by John Marshall (as a congressman) and approved by the Supreme Court (in U.S. v. Curtiss-Wright Export Corp in 1936), prohibits senators from making clear their positions on foreign policy matters. Senators can take votes that might oppose an executive branch policy. For example, the Senate passed a resolution opposing the Kyoto Accords, which effectively killed any chances of that treaty, and the American Servicemen’s Protection Act, which essentially defeated any hope for the International Criminal Court’s ratification by the U.S.

I, of course, have defended the sole organ authority of the president, probably more vigorously than any other law professor and few other government officials. But here the senators are not trying to negotiate with Iran or even trying to set out any terms for a deal. I thought the letter tried to avoid any substantive terms of the deal, but only went as far as stating clearly what U.S. constitutional law was (which I expect the Iranians already knew — or for which they paid advisors who could tell them). As a description of our constitutional law on international agreements, the letter was correct. What is the effective difference between sending the Constitution to the mullahs in an envelope, giving a speech reminding President Obama of the law of treaties, or publishing an op-ed criticizing the sole executive agreement? What would be best now would be for Senator Cotton to offer a Senate resolution opposing any sole executive agreement to limit Iran’s nuclear capability.