For months, Rex Tillerson consulted with America's European allies, Arab partners, Israeli friends and competing global powers on how Iran could be contained. In the coming months, however, the secretary of state's most important negotiating partners are in Washington. That is because the future of the nuclear deal, which the five permanent members of the U.N. Security Council and Germany concluded with Tehran two years ago, is now essentially in the hands of American representatives and senators.

Donald Trump may continue to reiterate that the nuclear agreement is a “disaster” and “the worst deal ever,” but as strongly as the president may take Iran to task, as his predecessor Barack Obama did, he appears to be shrinking away from the immediate termination of the deal. Rather, Trump hopes that Congress will offer a way out of the dilemma between aggressive Iranians, who in his opinion pulled the wool over Obama's eyes, and the co-signatories in Moscow, Beijing, Paris, London and Berlin, for they continue to view the pact as a success for peace diplomacy, or at least a tidy stopgap solution.

Does Trump Want To Pull the Plug Personally?

Almost nine months after taking office, nobody needs to explain to Trump how unforeseeable the consequences of his decisions are. Up until now, at least, the president has shown little aptitude in getting Congress to toe his line. Tillerson outlines three options for the representatives. Firstly, they could decide to do nothing. In that case, everything would remain the same, until Trump decides to pull the plug on the nuclear deal after all. Secondly, Congress could reintroduce the sanctions imposed as a result of Iran’s nuclear program, but which were suspended after the pact was signed. Such a violation would effectively void the deal. Or representatives and senators could follow the government's demand and make a sort of anticipatory resolution, namely a law that provides for immediate sanctions, for instance, in the event that Iran approaches the capacity to build an atomic bomb or to expand its missile program.

Such an automatic sanction could most easily be decided as an addition to the "Iran Nuclear Agreement Review Act"in which Congress, in 2015, required the president to certify every 90 days that Iran adhered to all requirements and that sanctions were "reasonable" for the Iranian counterparts. Tillerson said Thursday that Washington did not accuse the Iranians of a "technical" violation of the agreement.

Trump, however, did not want to certify to Congress a third time that the pact was in American interests, and chose what is called "Iranian decertification" in Washington's jargon. The president is hoping that Congress will pass a law that gives the deal some bite, gets allies to go on the offensive and wrests new concessions from Iran before the next certification deadline in January 2018. But that is not a firm deadline. Representatives and senators can take as much time as they want; and it is anything but certain they can agree on legal action.

The Situation Is Convoluted

As in the great domestic issues of health, immigration and tax policy, hard-liners and more moderate forces within the Republican factions argue over the Iran issue. In contrast to domestic policy, however, there should be no firm resistance front with the Democrats, which makes the situation even more confusing. There is also a great deal of concern among liberals about Iran's continued support for the Hezbollah militia and the Houthi rebels in Yemen, as well as aggressive hostility against Israel. Tillerson called for a series of concrete points of departure for new sanctions, but he himself remained vague.

The announcement by Republican Sens. Bob Corker and Tom Cotton must have given him hope that a joint draft bill could be submitted. As chairman of the Foreign Affairs Committee in 2015, Corker vigorously opposed the nuclear treaty, but considers an overly hasty dismissal with skepticism. He has developed into one of Trump’s most powerful critics. On TV on Sunday, he accused the commander-in-chief of running the United States like a "reality TV show" and possibly leading the country into a "third world war." Cotton, on the other hand, is an up-and-coming Trump loyalist, who has for years been the most enduring of all opponents of the nuclear deal. Both now suggest that America should automatically apply sanctions to Iran, if intelligence services were to determine that Iran needed only one year to build an atomic bomb. Rocket testing should also automatically incur penalties.

Eliot Engel, a Democratic foreign policy expert, was skeptical.* “Congress has a role to play in foreign policy, but we cannot pass a law to unilaterally change an international agreement,” the congressman said. Tillerson denies that that is the purpose. The law that is sought would co-exist peacefully with the nuclear deal. On the other hand, it would balance the weaknesses of the pact. According to the view of Trump’s administration, there are two major shortcomings. First, the nuclear agreement was too narrow, and Iran was freed from the sanctioning force without Tehran having to give up its "destabilizing activities in the region" or its support for terrorism. Second, Washington is concerned about the fact that Iran is only required to suspend most nuclear activities for certain periods; the country could therefore be back on the threshold of becoming a nuclear power within a few years.

Tillerson insists that Congress should demonstrate American resolve to the Europeans and other powers so clearly that they adopt similar resolutions, thus pushing Iran into new concessions. But the Iranians have made it clear that the deadlines laid down in the nuclear deal are not negotiable. Tillerson claimed that he would not pretend that such negotiations would be a sure-fire success. “It's possible we won't be able to make a deal,” he added.

Trump Disappoints the Expectations of Hard-liners

But at least America wants to make a start and is already trying to plan with partners for the time when Iran can again enrich uranium in a big way after the agreement. Sen. Cotton never forgets to point out how America could exert pressure to European allies. Above all, Washington can cut off Wall Street banks from doing business with Iran. Even the vague threat of such "secondary actions" slows European-Iranian business.

Judging by his campaign promise that he would "shred" the Iran nuclear deal, Trump has been led by Tillerson and other advisers toward a moderate path with an uncertain destination. In all the more drastic words, the president and his advisers promise that they will take the fight to the Iranian Revolutionary Guards. The talk is of harsh sanctions against companies that belong to the empire of the Revolutionary Guards. Tillerson wants to bring Europeans and other partners on board to create the most effective sanctions regime possible.

However, Trump has also disappointed hard-liners’ expectations because the United States will not list the Revolutionary Guards as a terrorist group for the time being. Since it is, for all intents and purposes, a “whole army,” Tillerson stated self-consciously, such a step would lead to complications, if “we run into one another in the battlefield.” Tillerson preferred not to acknowledge the fact that America's armed forces and Iran's Revolutionary Guards are de facto allies in the fight against the Islamic State.

*Editor’s note: Eliot Engel is the U.S. Representative for New York’s 16th congressional district.