President Donald Trump announced a bold shift in US policy toward Iran on Friday, declaring the nation a “rogue,” “murderous” state sponsor of terrorism performing short of its obligations under its nuclear deal with world powers.The president said he would order the Treasury Department to levy new sanctions against the “entire” Iranian Revolutionary Guard Corps for its “terrorist activity,” and declared that he could not certify under US law that Tehran’s actions under the nuclear accord were “proportional” to US sanctions relief.His decision not to certify means that Congress will reopen debate on the merits of the nuclear deal.The White House is working with Republican congressional leadership on “trigger” legislation that would impose new terms on parties to the nuclear deal, hoping to force a round of negotiations with Iran and international powers.“I am announcing today that we cannot and will not make this certification,” Trump said. “We need negotiators who will much more strongly represent America’s interests.”Trump wants to amend the Iran Nuclear Agreement Review Act of 2015 (INARA), an American law that provides Congress with oversight powers over the deal, reached that same year by the US, Russia, China, Britain, France, Germany and Iran.The amendment would “put in place some very firm trigger points” for the reimposition of sanctions, Secretary of State Rex Tillerson told reporters on Thursday night, previewing the president’s strategy.If Congress fails to pass the amendment, Trump threatened in a speech to the nation on Friday that he would pull out of the nuclear agreement entirely.“We will not continue down a path whose predictable conclusion is more violence, more terror, and the very real threat of Iran’s nuclear breakout,” he said, referring to a decision by Tehran to “break out” from a nuclear weapons capability to the construction of the weapons themselves. “In the event we are not able to reach a solution working with Congress and our allies, then the agreement will be terminated.“It is under continuous review,” he continued, “and our participation can be canceled by me, as president, at any time.”Trump said his proposed amendment – whose text has not been released, and is still a work in progress, sources say – would make “all restrictions on Iran’s nuclear activity permanent under US law.“I am directing my administration to work closely with Congress and our allies to address the deal’s many serious flaws so that the Iranian regime can never threaten the world with nuclear weapons,” he said. “These include the deal’s sunset clauses that, in just a few years, will eliminate key restrictions on Iran’s nuclear program. The flaws in the deal also include insufficient enforcement and near total silence on Iran’s missile programs.”He lamented that the Islamic Republic received much of its sanctions relief up front – a problem he cannot fix. But he said his administration was now focused on addressing other bad provisions of the agreement.“In just a few years, as key restrictions disappear, Iran can sprint toward a rapid nuclear weapons breakout,” Trump said. “In other words, we got weak inspections in exchange for no more than a purely short-term and temporary delay in Iran’s path to nuclear weapons.“What is the purpose of a deal that, at best, only delays Iran’s nuclear capability for a short period of time?” he continued. “This, as president of the United States, is unacceptable.”US legal triggers, if passed by Congress, would unilaterally “snap back” nuclear-related sanctions on Iran over its continued ballistic missile work – a component of its weapons program that was fiercely debated during the 2013-2015 nuclear talks and was ultimately left out of the deal entirely.It would also make those sanctions’ triggers permanent, with the intended effect of negating some of the expiration dates – or “sunset clauses” – built into the nuclear accord. Those clauses are of particular concern to the US, France and Britain, which believe that the deal provides Iran with a pathway to nuclear weapons.Decertification calls on Congress to consider “qualifying legislation” on Iran sanctions, and provides the Senate with a simple 50-vote threshold for their passage. But the amendment Trump will propose does not amount to qualifying legislation, and will instead require 60 votes – a far higher bar for the White House to pass, as it will require Democratic backing.Rep. Eliot Engel of New York, a leading Democratic voice on foreign policy, questioned the administration’s strategy in a statement on Friday. “The president’s plan doesn’t make sense,” said the lawmaker, who in 2015 opposed the nuclear agreement. “Negotiating additional terms to the nuclear deal requires a coalition of international partners, not unilateral congressional action.”And Ben Rhodes, former president Barack Obama’s deputy national security adviser for strategic communications and one of the architects of deal, warned that such legislation would torpedo the accord.“We’d be violating the deal,” Rhodes told reporters in a dueling conference call, made along with two other Obama-era officials involved in its original negotiation and implementation. “The clear line is passing legislation that gets into the space of the JCPOA.”But Senate Foreign Relations Committee chairman Bob Corker of Tennessee, who authored the review act, told reporters on Friday that he had a hand in crafting the White House amendment to his bill and had checked with State Department counsel on whether or not it would breach terms of the nuclear accord. Federal lawyers said it would not.“The legislation would not conflict with the JCPOA upon passage,” Corker and Republican Sen. Tom Cotton of Arkansas, who is also working with the White House, said in a joint statement. “Instead, it would set conditions that halt Iran’s nuclear program and provide a window of time for firm diplomacy and pressure to work.”National Security Adviser H.R. McMaster, who briefed Republican congressional leadership on Trump’s strategy on Wednesday, said, “There should be a lot of ground for bipartisan support. We think we have a real opportunity to impart a legislative remedy.”Tillerson, however, offered less optimism.“We don’t want to suggest this is a slam dunk on the Hill,” the secretary of state said. “We know it’s not.” But he noted that GOP leadership seemed enthusiastic about the strategy, and that Democratic leaders were not “outright rejecting” the amendment out of hand.Tillerson acknowledged that Tehran is unlikely to renegotiate the 2015 nuclear deal. But he thinks that Iran and other nations party to the deal might be willing to negotiate an addendum to it.The INARA amendment is Trump’s effort to get Congress on board with that diplomatic effort, Tillerson said.“Iran could just say, ‘Well we’re not interested in talking,’” Tillerson told reporters. “That’ll tell us something."