It became clear this week that opponents of the Iran nuclear agreement will not have the votes in Congress necessary to retract the President’s sanctions waiver authority by means of H.J. Res. 64, a resolution of disapproval. The President needed at least 34 “no” votes in the Senate in order to sustain his promised veto. With the addition of three more senators who announced Thursday that they will support the deal, the President may even reach 41 no votes, which would be the number required to successfully filibuster the measure designed to block the deal. If that happens, there is a chance the Senate Majority Leader wouldn’t even bring it to the floor, although there are significant political benefits to forcing the vote. More importantly, a filibuster would spare the President from having to use the veto.

Over the coming weeks we will move from the congressional acquiescence phase to the implementation phase. We now know that Congress will not formally prohibit the Iran deal. However, the deal will likely move forward under the weight of votes recording opposition from a majority of Senators and Representatives, which is not optimal as a matter of public diplomacy and resolve.

Now that the fate of the resolution of disapproval has become clear, some opponents of the Iran deal have started to float trial balloons about how to undermine the deal rather than defeat it outright. During the remainder Obama administration, most of those balloons will pop on the horns of the President’s veto power. However, there are some opportunities for opponents’ influence and mischief during the implementation phase.

A couple of ideas suggest that Congress do something short of categorical disapproval. For example, Orde Kittrie argues that Congress should pass language in the resolution of disapproval that would “specify what changes would be needed to meet congressional requirement.” He cites a long history of congressional rejections and conditions related to treaties and international agreements. He notes that “[o]ur negotiating partners should not be surprised if Congress takes the less drastic step of returning it to the President for renegotiation.” Express conditions from Congress could have the effect of making Congress appear more constructive than obstructionist. But that legislation would still have to overcome the President’s veto. Therefore, the persuasive value of this approach on the Senate membership vis-à-vis a veto-proof majority — and not its persuasiveness to domestic and international audiences — would be the only salient political effect.

Sen. Bob Menendez (D-NJ), who opposes the deal, suggested that Congress disapprove it but authorize the Joint Plan of Action, which would release $700 million per month while Iran negotiates in good faith. This, too, would be a modest signal of good faith on Congress’s part but it would again require a veto-proof majority due to President Obama’s opposition.

In a different approach, Sen. James Inhofe (R-Okla.) and Oklahoma’s Republican Attorney General Scott Pruitt argue that the states should sanction Iran notwithstanding the terms of the Iran deal. They cite provisions of the Comprehensive Iran Sanctions, Accountability, and Divestment Act of 2010 (CISADA) that authorize states “to divest the assets of the State or local government from, or prohibit investment of the assets of the State or local government in, any person that the State or local government determines … engages in investment activities in Iran.” CISADA Section 202(f) expressly disclaims federal preemption in order to avoid issues presented in Crosby v. National Foreign Trade Council and American Insurance Association v. Garamendi.

The Iran deal does nothing to withdraw state divestment authority. Secretary of State John Kerry confirmed in congressional testimony that the Iran deal, as an executive agreement, leaves that authority undisturbed. However, pursuant to the Iran deal, the administration agreed to “actively encourage” states to drop their sanction on Iran. Secretary Kerry stated that “if Iran is fully compliant with the agreement … we will take steps to urge [the states] not to interfere” by continuing sanctions.

The state authority provision is consistent with cooperative federalism of an aggressive and comprehensive Iran sanctions regime. However, now that the Executive seeks to ease sanctions on Iran pursuant to the deal, Inhofe and Pruitt seek to invoke the state authority in a spirit of uncooperative federalism. While the scope of state authority is limited to public monies, aggressive state sanctions identifying individuals and corporations as Iran business partners would frustrate Executive policy to a degree.

Areas in which Congress certainly has a continued role, and therefore leverage, are appropriations and oversight. Last month, Sen. Lindsey Graham (R-SC) threatened to withhold US funding for the International Atomic Energy Agency (IAEA) unless Congress is allowed to review the agreements between the IAEA and Iran designed to implement inspections and enforcement of Iran’s obligations under the deal. The United States provides around $88 million to the IAEA annually, which is approximately a quarter of its yearly budget. Given Graham’s role as chair of the relevant Senate appropriations subcommittee, it is not an idle threat. (A side note: I am working on a law review article that explores congressional oversight interests as applied to international organizations and foreign sovereigns that receive US funds.)

The Executive has periodic reporting requirements that will serve as oversight forcing functions. Sharon Squassoni and Chris Coughlin suggest that Congress establish a task force for Iran Deal Compliance or that the Senate reconstitute the Arms Control Observer Group as platforms for coordinated and sustained oversight of compliance with the nuclear agreement. Congressional leadership would have to weigh the policy coordination and public message value of a unified oversight platform against the likely resistance by committee chairs with existing oversight jurisdiction. In any scenario, a Congress that is inhospitable to the Administration’s Iran policy will continue to control appropriations and conduct oversight.

Three major events next year could also have a major effect on the implementation phase: (1) US congressional elections, (2) the US presidential election, and (3) the sunset of the Iran Sanctions Act. Congress could either remain opposed by a simple majority, increase opposition to veto override levels, or become supportive of the Iran agreement. The new President could change Iran policy, as several Republican candidates have promised to do.

Further, the sunset provision will force congressional action on our complicated Iran sanctions regime that will play into the election outcome dynamics. At present, Menendez and Sen. Mark Kirk (R-Ill.) have introduced legislation that would extend the Iran Sanctions Act by 10 years. Sen. Bob Corker (R-Tenn.) has promised to pass that legislation out of the Senate Foreign Relations Committee after the vote on the disapproval resolution. However, a successful extension will require normal bicameral passage and presentment. Therefore, legislation hostile to Executive policy would have to survive a veto, and negotiations will be conducted in a veto’s shadow.