US president Donald Trump blamed the Obama administration for lifting sanctions just as Iran's government was facing "total collapse".
"The previous administration lifted these sanctions, just before what would have been the total collapse of the Iranian regime."
An imminent collapse of Iran's economy was highly unlikely, according to international economists and US officials.
International penalties on Iran in response to its nuclear programme did drive its economy into crisis earlier this decade. But even before the nuclear deal, Iran had cut budget expenditures and fixed its balance of payments. It was still exporting oil and importing products from countries such as Japan and China.
The multinational deal froze Iran's nuclear programme in return for an end to a variety of oil, trade and financial sanctions on Tehran. Iran also regained access to frozen assets held abroad.
The deal was conceivably an economic lifeline for the state, but international economists as well as US officials did not foresee an imminent economic collapse at the time.
Among those experts, Patrick Clawson at the Washington Institute for Near East Policy said Iran's leaders worried about the potential for social unrest at the time, but that the economy was sustainable.
"The Iranian regime has committed multiple violations of the agreement. For example, on two separate occasions, they have exceeded the limit of 130 metric tons of heavy water."
Iran is meeting all of its obligations under the deal, according to International Atomic Energy Agency investigators, who noted some minor violations that were quickly corrected.
Mr Trump is right that Iran exceeded the limit on heavy water in its possession on two occasions. Both times, international inspectors were able to see that Iran made arrangements to ship the excess out of the country so that it could come back into compliance.
Deal supporters argue this shows the agreement works. Opponents say that because Iran sells the surplus on the open market, it is therefore being rewarded for violating the deal.
Mr Trump and other critics of the agreement point in particular to Iran's continuing missile tests, which may or may not defy the United Nations Security Council resolution that enshrined the deal. But those tests do not violate the deal itself.
"It also gave the regime an immediate financial boost and over $100bn its government could use to fund terrorism. The regime also received a massive cash settlement of $1.7bn from the United States, a large portion of which was physically loaded on to an airplane and flown into Iran."
The "financial boost" was from money that was Iran's to begin with. It was not a payout from the US or others but an unfreezing of Iranian assets held abroad.
The $1.7bn from the US is a separate matter. That dates to the 1970s, when Iran paid the $400m for military equipment that was never delivered because the government was overthrown and diplomatic relations ruptured.
The rupture left people, businesses and governments in each country indebted to partners in the other, and these complex claims took decades to sort out in tribunals and arbitration. For its part, Iran paid settlements of more than $2.5bn to American people and businesses.
The day after the nuclear deal was implemented, the US and Iran announced they had settled the claim over the 1970s military equipment order, with the US agreeing to pay the $400m principal along with $1.3bn in interest.