“When you look at the Iran deal — I think it’s terrible,” the president explained. “I guess he thought it was okay. I wanted to either break it or do something. And he felt a little bit differently. So we were not really thinking the same.”

Tillerson had been widely credited with convincing the president to recertify Iran’s compliance with the nuclear deal, formally known as the Joint Comprehensive Plan of Action, early in his presidency. Under the terms of congressional ratification of that agreement, the president is required to report on the status of the deal and its impact on national security every 90 days.

After granting certification twice, Trump finally refused to do so again at the time of the deadline last July. But he did not then take direct actions to cancel or undermine the JCPOA, presumably as a result of intervention from Tillerson and other members of his foreign policy team.

The White House as a whole has expressed concern over perceived deficiencies and mistakes in the agreement, which was concluded in July 2015 between Iran and six world powers headed by the Obama administration. But opinions have evidently varied regarding the tactics for addressing those deficiencies.

Other dissenting voices reportedly include Secretary of Defense James Mattis and Chairman of the Joint Chiefs of Staff General Joseph Dunford. On Tuesday, Reuters pointed to previous public comments from both these men, which credited Iran with upholding its basic obligations under the JCPOA and advocated for keeping the US in the agreement for the time being. The report also noted that General Joseph Votel, the head of the US military’s Central Command, warned against withdrawal on Tuesday, saying that “if the JCPOA goes away then we will have to have another way to deal with their nuclear weapons program.”

President Trump has correctly declared that he can utilize his authority to pull out of the agreement at any time, yet he has apparently deferred to the more pragmatic voices in his administration. However, those voices are presumably wielding less influence over time, and Tillerson’s firing is only one sign of this shift.

In January, Trump renewed the sanctions waivers that were put into place by a deal he had already decertified. This represented another instance of his passing the issue to Congress, which he had instructed to shore up the weaknesses in the deal. But Trump warned that this was the last time he would decline to revoke American participation in the JCPOA unless congressional actions succeeded in satisfying his demands. The sanctions will be due for another renewal in mid-May, and the president is not expected to grant that renewal in absence of an agreement that would effectively supplement the nuclear deal.

There are persistent doubts over whether Congress can secure such an agreement with European partners who are also signatories to the JCPOA. But the change in leadership at the head of the State Department may contribute to further escalation in pressure on these partners and on Congress regarding issues such as Iran’s ballistic missile program, sunset clauses in the nuclear deal, and access to Iranian military sites by inspectors from the International Atomic Energy Agency.

CNBC greeted the news of Pompeo’s appointment with the declaration that it is “probably bad news for Iran.” The report explained that the current CIA director has expressed views on Iran that are much closer to Trump’s hardline position, which included support in December and January for an uprising by Iranian citizens whom he described as “fed up with [the] regime’s corruption & its squandering of the nation’s wealth to fund terrorism abroad.”

For his part, while serving as Secretary of State, Rex Tillerson outlined an Iran policy that included support for domestic movements that could facilitate the “peaceful transition” of the nation’s government. But his pending replacement has arguably employed far stronger rhetoric against the clerical regime, explicitly comparing it to the Islamic State militant group and calling it a “thuggish police state” in a speech last October.

Pompeo has also expressed commitment to curtailing global investment in the Islamic Republic while also attacking the nuclear agreement that made much of that investment possible. The Trump administration’s well-known opposition to the JCPOA has already been credited with slowing the pace of such investment. Some of the president’s supporters have even urged him to withdraw licenses for the sale of commercial aircraft to Iranian carriers by the US-based manufacturer Boeing. Pompeo’s record suggests that he is more likely to support such extreme measures than other advisers.

Market Watch suggested on Tuesday that oil prices were already reacting to the news of the pending change at the head of the state department, with slight increases in the price of Brent crude, the global oil benchmark, among other petroleum commodities. This may reflect a rise in expectations of renewed US-led sanctions on Iran’s oil economy.

Since shortly after the implementation of the JCPOA in January 2016, Iranian officials have been complaining that these concerns had slowed the pace of Iran’s economic recovery. On their view, the US government’s discouragement of foreign investment in Iran constituted a violation of the “spirit” of the nuclear deal. Those same officials have suggested that they would pull Iran out of the agreement if the situation did not change – an act that would effectively take the withdrawal decision out of the hands of the Trump White House.

In light of Pompeo’s clear threats against foreign investment in Iran, it is increasingly likely that Tehran will find itself in the position to either follow through on these longstanding threats or else admit to the regime’s bluff.