The Australian foreign affairs minister has said there is a “powerful argument” that U.S. President Donald Trump’s threat to scrap the 2015 nuclear deal between Tehran and world powers could imperil efforts to negotiate a peaceful outcome with North Korea.

Julie Bishop said she had asked U.S. officials, including Secretary of State Rex Tillerson, how they would counter the argument that North Korea could not trust the U.S. if it walked away from its previous international agreements, The Sydney Morning Herald reported.

By endorsing the argument that ditching the deal could set back efforts to negotiate with North Korea over its nuclear program, Bishop is, in fact, pressuring the White House not to push ahead with what many international experts say would be a self-defeating move but one in which Trump is personally invested.

Bishop added that she had discussed the matter with American officials last month after Iran mounted the argument to the United Nations General Assembly that the U.S. would lose credibility including in its stand-off with North Korea.

On October 13, Trump refused to certify that Iran is complying with the accord. But Trump, breaking his campaign pledge to rip up the agreement, did not pull the U.S. out or re-impose nuclear sanctions against Iran.

Trump instead punted the issue to Congress, instructing lawmakers to toughen the law that governs U.S. participation in the deal and calling on the other parties to the accord to fix a series of deficiencies.

Recently, Leader of the Islamic Revolution Ayatollah Ali Khamenei warned that Iran would “shred” the nuclear deal, also known as the Joint Comprehensive Plan of Action (JCPOA), if Trump tears it up.

Iran and the P5+1 group (the five permanent members of the UN Security Council plus Germany) reached the 159-page nuclear agreement in July 2015 and implemented it in January 2016.

Since the historic deal was signed in Vienna, the International Atomic Energy Agency (IAEA) has repeatedly confirmed the Islamic Republic’s compliance with its commitments under the JCPOA, but the U.S. has failed to live up to its undertakings.