By law Trump has to certify the deal Iran Nuclear Agreement Review Act (Inara) every three months.
This deal, officially the Joint Comprehensive Plan of Action (JCPOA), was signed in July 2015 between Iran, the five permanent members of the UN Security Council (the US, Russia, France, the UK and China) plus Germany.
It was a diplomatic victory for Iranian President Hassan Rouhani.
The partial lifting of Western sanctions was a direct result, leading to a flurry of economic activity and an increase in imports.
But the lifting of sanctions did not lead to an overall improvement of the living standard of the average Iranian.
In December Rouhani came under pressure as thousands took the street in several cities in Iran to protest against their economic conditions.
When protests turned against the government, the Revolutionary Guard militias stepped in and may have arrested more than 1,000 people, according to Iranian MP Mahmoud Sadeghi.
US slams crackdown
The US House of Representatives voted 415-2 the House Resolution 676 “supporting the rights of the people of Iran to free expression, condemning the Iranian regime for its crackdown on legitimate protests”.
But Iran scoffed at the resolution.
“If the US Congress was interested in human rights,” says Foad Izadi, an America specialist with the Univerisity of Tehran, “they could have stopped selling billions of dollars' worth of weapons to the Saudi government that is bombing its neighbours, killing women and children on a daily basis.
“So the people of Iran see this type of hypocrisy, supporting human rights in one instance and helping to crush human lives in other instances, this feeling is not that great."
The latest US vote may well be the shape of things to come.
This time round awmakers may not want to miss the 60-day deadline to support Trump’s decertification.
Other countries involved
Then again, the US is not the only partner in the JCPOA. Russia and China back Iran traditionally, but France, the UK and Germany have also indicated they want to stick to it.
Iran’s Foreign Minister Mohammad Javad Zarif is to meet EU leaders in Brussels on Thursday, in an attempt to make sure that the European players will stand by their commitments.
The Europeans may not like it if the Trump government distances itself from the hard-won deal.
“It will worsen the [trans-Atlantic] relationship and it will complicate it even further,” says Ghanem Nuseibeh, director of Cornerstone Global Associates, a thinktank based in London.
The Europe-US relationship suffered a severe blow when Trump declared that the Washington recognised Jerusalem as Israel’s capital.
The UN General Assembly overwhelmingly rejected the decision with 128 countries, including France, Germany and the UK, calling on the US to change its mind, 35 abstaining and only nine backing Trump's move.
"Interestingly on this one, I think although there might be a further wedge between the Americans and the Europeans, I think that the Arab countries will in fact welcome an escalation with Trump,” says Nuseibeh.
“So perhaps on the Jerusalem decision you had the US versus Europe and the Arab world. On this one you might have the US and the Arabs against Europe.
“So he is really mixing up the way that global politics are being addressed."
Israeli Prime Minister Benjanmin Netanyahu is likely to welcome decertification if it takes place.
But not everyone in Israel is against it.
“I think that the agreement is not that good,” says Efraim Esculai, a nuclear scientist with the National Institute of Security Studies in Jerusalem; “but abandoning it now would be a mistake. What has to be done is to approve its application.
"The International Atomic Energy Agency (IAEA) changed its policy about reporting to the public, to reporting to the member states. It has adopted a policy of confidentiality which is not warranted. I think the reports have to be much more open and that has to be insisted upon. At the moment no one insists on anything, almost anything.
If Trump decertifies the deal again, Congress has until 12 March to put it to a vote.