By Parisa Hafezi and Michelle Nichols
DUBAI/NEW YORK (Reuters) - The fate of a fragile 2015 nuclear deal between Iran and world powers hinges on the result of the U.S. presidential election in November, not a planned U.S. bid this week to trigger a return of all U.N. sanctions on Tehran, said several Iranian officials.
When Iran agreed to sanctions relief in return for curbs on its nuclear program, Tehran warned that it would no longer stick to the deal if any of the parties sparked a so-called snapback of sanctions at the U.N. Security Council, a backstop included in the accord in case Iran stopped complying.
U.S. President Donald Trump's administration plans this week to use that snapback provision, even though it quit the deal in 2018 and the move is opposed by the remaining parties to the accord - Germany, Britain, France, Russia, China and Iran.
But despite Tehran's declaration five years ago, three senior Iranian officials told Reuters that Iran's leadership is determined to remain committed to the nuclear deal, hoping that a victory by Trump's political rival Joe Biden in the Nov. 3 presidential election will salvage the pact.
"Right now the decision is to remain in the deal even if Americans make their biggest mistake of triggering the snapback mechanism," said a senior official, on condition of anonymity, who is involved in the discussions about Iran's nuclear policy.
"We will be still here, but Trump might not be at the White House in a few months," the official said.
Biden has said he would rejoin the nuclear deal, but only if Iran first returned to compliance. The accord was agreed by former U.S. President Barack Obama's administration, when Biden was vice president.
A second Iranian official - a former nuclear negotiator - said Iran was "technically and politically" ready to quit.
"But we have to be smart and not to fall in the U.S. trap which wants to push Iran out of the deal," said the official, speaking on condition of anonymity.
Iranian Foreign Minister Mohammad Javad Zarif has described the next few weeks and months as critical for the nuclear deal.
To trigger a return if all U.N. sanctions on Iran the United States will submit a complaint to the 15-member Security Council about Iran's non-compliance with the nuclear deal.
In response to what Washington calls its "maximum pressure" campaign - a bid to get Iran to negotiate a new deal - Tehran has breached several central limits of the 2015 deal, including on its stock of enriched uranium.
But diplomats say the snapback process will be tough and messy as Russia, China and other countries on the Security Council challenge the legality of the U.S. move given Washington itself is no longer complying with what Trump called "worst deal ever" and has imposed strong unilateral sanctions on Iran.
A European diplomat, speaking on condition of anonymity, said that the U.S. move to spark a return of all U.N. sanctions would risk "destroying" the nuclear deal, but "it will be a completely contested procedure so the snapback will have no effect, it will not be recognized by others."
The United States argues it can trigger the return of the sanctions because it is still named as a participant to the nuclear deal in a 2015 U.N. Security Council resolution that enshrines the agreement.
A second European diplomat, speaking on condition of anonymity, said "the overwhelming majority of the international community" believe the United States cannot trigger snapback.
Outgoing U.S. Iran envoy Brian Hook said on Tuesday that the nuclear deal, while well intentioned, had failed to deter Iran.
"We have put in place enormous leverage for a (Trump) second term to get the kind of outcomes that we're going to need," he told a United Against Nuclear Iran think tank event.
(Additional reporting by Sabine Siebold; Writing by Michelle Nichols; Editing by Alistair Bell)