The deal’s provisions mostly last just 10 to 15 years and this is the Trump administration's main concern, because it means they see the deal as just putting off Iran's acquisition of nuclear weapons.
Sanam Vakil, an Iran analyst at Chatham House in London, explains that "in 10 years, Iran is legally entitled to start a peaceful nuclear energy programme and that is what concerns conservatives in the States. Because the lack of trust resulting from 40 years of no diplomatic relationship, coupled with longstanding grievances on regional issues, the Republicans fear that Iran will recommence its clandestine nuclear weapons programme."
Trump's Republican Party has shown longstanding mistrust towards Iran, especially in light of its support for armed groups in the Middle East such as Hamas and Hezbollah. And while such Iranian actions might not be directly relevant to the deal, they are still driving the Trump administration's fears about it.
These fears "have more to do than with the provisions or the technicalities of the deal than with an overall perception towards Iran as a regional actor, as a regime - and the tendency in the new administration has been to mix these things," says Aniseh Bassiri Tabrizi, Iran expert at RUSI in London.
Monitoring Iran's compliance
It seems that abandoning the deal could be much more problematic than the Trump administration suggests. The accord does not just involve the US and Iran. It was also signed with Britain, France, Germany, Russia and China, through the UN.
Furthermore, “in the absence of a deal, there would be nothing to monitor Iranian behavior", adds Vakil.
There has been much debate over whether the deal has had a significant impact on the Iranian government. When he signed it, then US President Barack Obama said he hoped it would open Iran up to the world.
"I think it was overambitious for President Obama to promise or to hope that the deal would result in an immediate moderation of Iranian domestic politics and Iranian foreign policy,” says Sanam Vakil.
“But, at the same time, one could also say that President [Hassan] Rouhani (who is not a reformist, he's a centrist), a balanced political leader, was reelected with a larger majority than he was in 2013, suggesting that the Iranian people continue to support the deal."
Thus, from what the two experts have said, it seems that Macron's view of the Iran deal might just win out over Trump’s.