Iran's sectors of banking, oil and gas, and automotive would probably lose global partners, according to the country's financial analysts.
Paul Sheldon, chief geopolitical advisor in Dubai Office of S&P Global Platts Analytics, said the new sanctions will place around 200 million barrels per day of Iranian crude exports at risk by the end of 2018.
Meanwhile, regulatory uncertainty could cause some importers to cut shipments immediately, Sheldon estimated, saying U.S. allies including Japan and South Korea are likely to comply and reduce imports, while certain companies in the EU will likely avoid any risk of running afoul of U.S. law.
Furthermore, already troubled financial transactions by Iran would be further frustrated in the country's attempt to rejoin global markets and banking systems.
Washington is not meeting its commitments under the deal to remove barriers to allow the country's full engagement in international finance and commerce, said Hommod Friad, an economic researcher with a data study institution in Tehran.
The U.S. significance to international banking will weaken the ability of European and Asian companies to help ease Iran's economic pain, Friad said. "Any cooperation or investment plan involving Iran will be put on hold again."
Before Trump's announcement, Rouhani had said "if our expectations from JCPOA are met without the United States, so much the better."
However, unless there is a recovery in the country's economic and investment prospects, Iran's commitment to the deal could gradually erode following the U.S. withdrawal, resulting in its eventual collapse, observers commented.
REPERCUSSIONS
The United States could face a backlash by leaving the deal.
The International Atomic Energy Agency, which monitors Iran's compliance with the deal, has issued several reports confirming Iran has fulfilled its responsibilities under the agreement.
What's more, this nuclear deal is not a bilateral deal between Iran and the United States. The decision to unilaterally withdraw from the deal will take a toll on the U.S. international image and its credibility in foreign affairs.
Meanwhile, Iran could respond by punishing U.S. allies in Syria, Iraq, Yemen and Lebanon.
Iran has also threatened to target U.S. forces exposed in Afghanistan and Iraq.
Moreover, the consequences of having no deal would go beyond proliferation. There is a likelihood that Saudi Arabia and other regional powers would also seek dual-use nuclear technology.
"Trump's withdrawal undermines the confidence and appetite of other potential nuclear proliferators to resolve similar issues via negotiation. Dialogue is always the best way to resolve the non-proliferation issue. If Iran's agreement can be so easily broken, why should people negotiate?" noted Friad, the economic researcher.
PUBLIC REJECTION
Public opinions in the region, especially in Iran and the Arab states, appear mostly opposed to Trump's decision, hinting their worries over further instability and Western pressures anew.
Gaza resident Abu Mohammed said, "Trump has frequently threatened other countries since he became U.S. president."
Ameer Turk, another Gaza resident, expressed deep worries that there would be a war in the region, saying the withdrawal from the deal is "a withdrawal from commitments to Iran, Europe and the world."
Washington has not honored its commitments under the 2015 international nuclear deal, said 25-year-old Zohreh Torabee, a law student at a Tehran university.
Majority support for the deal was buoyed by some optimism that the deal would eventually improve living conditions. That would unlikely be the case with the United States vacating the deal.
"Iranian people are sick of the same sanction games being played out over and over by the Americans, and have decided to resist the pressures," said Mohsen Kenofed, a middle-aged bookseller, expressing optimism that "we will hopefully overcome the hardship."
Nima and Mojgan, a young couple in the Iranian capital, said Trump's hostile approach towards their country has only made things worse for himself.
"At the end of the day it's us who will win the game," Mojgan said.
