WASHINGTON ― President Donald Trump will announce on Friday afternoon that he is decertifying the Iran nuclear agreement while simultaneously urging Congress not to kill the deal. Instead, he’ll call on Congress to revise a related law to alter U.S. commitments under the international agreement ― a move that could itself kill the accord.

Trump’s plan follows a lengthy interagency review and months of speculation about whether he would scrap the 2015 Joint Comprehensive Plan of Action, which imposed restrictions on Iran’s nuclear program in exchange for sanctions relief. Secretary of State Rex Tillerson previewed the president’s announcement for reporters ahead of Trump’s speech.

Iran is “under technical compliance” with its obligations under the agreement, Tillerson said ― but Trump has decided he cannot certify that the sanctions relief the U.S. is providing Iran under the nuclear agreement “is proportionate” to Iran’s efforts to constrain its nuclear program.

Because of an oversight law passed by Congress in 2015, which the Obama administration reluctantly signed, Trump’s decision to decertify the international agreement will trigger a 60-day period, during which time Congress can fast-track legislation to reimpose sanctions against Iran with a simple majority vote in the House and the Senate. But Trump will ask Congress not to take that step, Tillerson said, acknowledging that doing so would likely kill the agreement.

Instead, Trump will ask Congress to revise the oversight law to include “some very firm trigger points” that would cause sanctions to automatically be reimposed if Iran took certain steps related to its nuclear program and its ballistic missile program, Tillerson said. Although most of the provisions in the Iran nuclear deal expire ― or “sunset” ― after 10-15 years, these “firm trigger points” would have no expiration, he said.

Trump will also direct the Treasury Department to impose additional sanctions against individuals and entities linked to Iran’s Islamic Revolutionary Guards Corps for the group’s “support of terrorist activities in the region,” Tillerson said. The administration is not designating the entire IRGC as a foreign terrorist organization at this time because of potential complications if the U.S. troops encounter IRGC troops on the battlefield, he added.

Trump has promised since the presidential campaign that he would either scrap the Iran deal or renegotiate it to make it more favorable to the U.S. Throughout the interagency review, Trump’s top advisers urged him against scrapping the deal and warned him that other parties to the agreement were not open to re-litigating its terms.

If the Trump administration’s goal is to keep the nuclear agreement in tact, but strengthen some of its provisions, it’s not at all clear how that plan would work.

Iran is likely to view these “trigger points” as the U.S. unilaterally changing its obligations under an agreement that was painstakingly negotiated between seven countries. Russia and China ― and possibly some of the U.S. European allies who signed the accord ― are likely to side with Iran on this matter. If Congress amended the existing oversight law as Tillerson suggested, the U.S. would no longer honor sunset clauses that were agreed to in the 2015 nuclear agreement and would impose new penalties against Iran in relation to its ballistic missile program ― an issue that was not covered by the nuclear deal.

Trump’s plan “seems to be predicated on the erroneous belief that getting Congress to unilaterally legislate new terms for the agreement will convince Iran and the other parties to capitulate to U.S. demands in exchange for no new benefits,” Jeremy Ben-Ami, president of the progressive pro-Israel group J Street, said in a statement.

“This gambit risks not only putting the U.S. in breach of the agreement. It also aligns our European allies with Iran in defense of the deal thereby slashing U.S. leverage in any additional diplomatic efforts to constrain Iran’s nuclear and non-nuclear activities,” Ben-Ami added.

It is also not at all clear that Congress will be able to amend the oversight law. Under regular order, a revised bill would need 60 votes to pass in the Senate, meaning all Republicans and eight members of the Democratic caucus would have to support the move. Although every Republican and a handful of Democrats voted against implementing the nuclear agreement in 2015, prominent critics have since urged Trump to abide by the existing deal.

“I don’t want to suggest to you this is a slam dunk on the Hill, we know it’s not,” Tillerson told reporters. There is a chance that lawmakers could opt to leave the issue alone, in which case Trump’s decertification announcement would have no immediate effect on the Iran nuclear deal.

Trump could, of course, reimpose sanctions himself using executive authority any time he chooses ― but he would be left responsible for the negative consequences of doing so.

The administration’s new plan appears to be a delicately crafted effort by his advisers to give the president the chance to deliver a tough-sounding speech on Iran while tossing the consequential part of the decision about the nuclear accord’s future to Congress ― where Trump’s vision could stall, like his plans to legislatively repeal Obamacare have.

After Tillerson briefed reporters on the details of the Trump administration’s Iran strategy, the White House sent out a “Fact Sheet” titled: President Donald J. Trump’s New Strategy on Iran. But the factsheet didn’t lay out any specific policy plans. Instead, it included a meandering list of grievances the the Trump administration has against the Iranian government.

Although Trump has repeatedly trashed the Iran nuclear deal, he has faced massive resistance to pulling out of or taking steps that could kill the agreement. The International Atomic Energy Agency, tasked with monitoring the use of nuclear energy, has continued to verify Iranian compliance with its commitments under agreement. The U.S. intelligence community found no evidence to challenge those findings, and State Department officials have overwhelmingly advocated remaining party to the deal.

Secretary of Defense James Mattis testified earlier this month that abiding by the agreement is consistent with U.S. national security interests. And U.S. allies in Europe who helped negotiate the agreement have made clear that they are not interested in re-litigating its terms.

For its part, Iran has repeatedly warned that it could consider the agreement null if the U.S. doesn’t hold up its end of the bargain. That could mean that Iran would ramp up its nuclear program and deny access to international inspectors who have been monitoring its nuclear sites.

After media outlets reported Trump’s plan to decertify the Iran deal and toss the issue to Congress, lawmakers who had previously criticized the agreement indicated they were not necessarily ready to help kill it.

“As flawed as the deal is, I believe we must now enforce the hell out of it,” House Foreign Affairs Committee Chairman Ed Royce (R-Calif.) said shortly before Trump was expected to announce his decision. In 2015, Royce introduced a resolution attempting to block implementation of the nuclear accord.

Several other Congressional Republicans, who once unanimously opposed the agreement, have expressed discomfort with backing out of the Iran deal in the face of Trump’s move to decertify it.

Influential Democrats who broke with Obama in 2015 over the nuclear deal are also now urging Trump to enforce it. Rep. Eliot Engel (N.Y.) and Sen. Ben Cardin (Md.), the top Democrats on the House and Senate committees that focus on foreign affairs, have reversed their opposition to the agreement.

Killing the deal would be a “grave mistake” now that it is in place and has the support of U.S. allies, Engel said. Cardin has aggressively pressured the Trump administration to certify Iran’s compliance and issued public reminders underscoring the lack of evidence about Iranian violations of the agreement.

Critics-turned-supporters of the deal say that it is too late to pull out now, especially without evidence that Iran is cheating.

“It would send a terrible signal to other states ... if Washington were to abrogate a treaty simply because of a change of administrations,” Max Boot, a foreign policy analyst who had initially opposed the agreement, wrote for Foreign Policy. “Why would anyone trust Washington to keep its word ever again?”

Asked a similar question by a reporter, Tillerson said he wasn’t worried about the message the administration’s plan would send to other countries. “I think they can trust we’ll never do a deal this weak again.”