Critics of the new Strategic Arms Reduction Treaty (START) warn that it may endanger the United States' capacity to go forward with missile defense. But the treaty, Senate consideration of which has been pushed back to the fall, raises another concern. Consent to it as it stands will further erode the Senate's constitutional role in American foreign policy.
This treaty does not constrain future development of missile defense (except in a few limited ways). It does, however, create a Bilateral Consultative Commission with power to approve "additional measures as may be necessary to improve the viability and effectiveness of the treaty." The U.S. and Russian executive branches can implement these measures and thus amend U.S. treaty obligations -- without returning to the U.S. Senate or the Russian Duma.
Could the commission constrain missile defense? It is empowered to "resolve questions related to the applicability of provisions of the Treaty to a new kind of strategic offensive arm." The treaty's preamble recognizes "the interrelationship between strategic offensive arms and strategic defensive arms." The commission might have jurisdiction over missile defense through this interrelationship. Russia has already warned that it might withdraw from the treaty if the United States develops missile defenses. Limits on missile defense systems thus might be "necessary to improve the viability and effectiveness of the Treaty."
Supporters say the treaty allows the commission to make only changes that, in the words of one State Department official, "do not affect substantive rights or obligations under the Treaty." This assurance provides little comfort. New START does not explain what counts as a "substantive right," and the commission, which is given very broad power to interpret the treaty, will itself decide the issue.
It is true that the amendment procedure contemplated in the new treaty is similar to one in the original START and that amendment procedures of this sort have been embedded in arms control agreements for decades. Also, the president has long exercised an independent authority to make new international agreements that implement treaties. Why should the Senate care about this issue now?
One reason is that as treaty delegations of this sort have expanded, and as more authority for making international agreements is transferred to the executive branch and international organizations, the cumulative effect of these arrangements becomes increasingly hard to square with the Senate's constitutional role in the treaty-making process and, more generally, with separation of powers.
Some courts have begun to give credence to this concern. In 2006, the federal appellate court for the District of Columbia declined to implement the "adjustments" that an international organization had made to an environmental treaty even though the political branches agreed to the adjustment process. The court noted the "significant debate over the constitutionality of assigning lawmaking functions to international bodies" and held that treating the treaty adjustments as law "would raise serious constitutional questions in light of the nondelegation doctrine, numerous constitutional procedural requirements for making law, and the separation of powers."
Another reason is that courts often look to the practice between the branches of government in determining constitutional limits. If the Senate continually acquiesces in delegating international lawmaking to the president and international organizations, courts are unlikely to protect senatorial power in the end. Moreover, arms control treaties such as New START rarely come before courts.
In short, only the Senate can protect its constitutional prerogatives.
One way for the Senate to do this would be to condition its consent to the treaty on an interpretive "understanding" that the commission's amendment power extend only to technical treaty matters and not to limitations on missile defense. Understandings of this sort are common in U.S. treaties. The Senate could also condition consent to the treaty on a requirement that it be notified about deliberations of this commission.
Such provisions would preserve the commission's core authority while constraining it in ways that eliminate the most serious constitutional objections. They would also lay down a marker about the Senate's role in this context.
The State Department insists that "there were no secret deals made in connection with the New START Treaty; not on missile defense or any other issue." If that is true, the administration should have no problem with minor Senate tweaks of this sort. If the administration does have a problem with them, the Senate should worry -- about the commission's power to limit missile defense, the executive's attempt to limit the Senate's constitutional role in the treaty process, or both.
Jack Goldsmith, who teaches at Harvard Law School and is on the Hoover Institution Task Force on National Security and Law and Jeremy Rabkin, who teaches at George Mason Law School.