That precedent of non-self-execution anchors US commitments in domestic law – key to credibility and multilateralism.

Unilateral presidential authority over treaties reduces their strength as a signal of commitment. Requiring approval by both branches increases the political costs of treaty termination. Either the Senate may be unwilling to terminate or the President may have to expend political capital to persuade a supermajority of Senators, and at the very least coordinating both branches’ actions can be costly even when controlled by the same political party. Requiring legislative approval bears resemblance to the idea of audience costs because the President will have to make political commitments to the Senate and perhaps the House to consent to treaty termination. His political promises may backfire if he cannot follow through on the foreign policies accompanying withdrawal. The current practice, however, does not require congressional consent. Presidents today need not incur political costs to persuade the House and Senate to agree to treaty termination, which makes treaties a less valuable sign of commitment.

A non-self-execution approach like that of the CWC, however, may cure this problem. If a treaty cannot take domestic effect without legislative implementation, an international agreement will usually require the participation of the House. As an act of Congress, the implementing legislation will require another act of Congress for repeal. A President’s termination of a treaty will dissolve the formal legal obligation, but the policy of the United States will still continue because he cannot repeal the implementing legislation. For example, even if the President withdrew the United States from the Chemical Weapons Convention, the CWCIA would still make the possession of chemical weapons a federal crime. Executing legislation has the effect of creating a mechanism similar to John Jay’s proposal for Senate consent to treaty withdrawal. While the votes required would demand a majority of both Houses rather than two-thirds of the Senate, the filibuster rule in the Senate would still allow a minority of states to block repealing legislation.

Notice that the rule of non-self-execution allows the United States to send varying degrees of signals about its commitment to an international agreement. A sole executive agreement may provide the weakest sign, because it will only survive as long as the President in office chooses to follow policies consistent with the pact. A treaty standing alone provides a great deal of information to another nation but it does not provide a much higher level of commitment. A treaty plus an implementing statute creates the highest level of American commitment because to renege on the promises demands the cooperation of the President, Senate, and House together. No one branch can terminate both the international agreement and the accompanying domestic policy. Non-self-execution, in other words, may help improve the achievement of American foreign policy goals. A non-self-execution regime gives the United States more tools to overcome the enforcement obstacles to international agreements and allows the United States to better reap the benefits of international cooperation.