The U.K., Germany and France set a June deadline for a new Iran deal in order to leave time to snap back sanctions on the Islamic Republic if it does not agree to give up its nuclear program, U.K. Ambassador to Israel Simon Walters said on Tuesday.

Walters, speaking at the Institute for National Security Studies’ annual conference in Tel Aviv, said while Iran is in “total breach of the JCPOA,” the 2015 nuclear deal, by enriching uranium beyond a level for which there is a civilian justification, there is currently “an important opportunity” to reach a new agreement, with Iranian leaders and President Donald Trump saying they want to restart talks.

The E3 – a term for the European parties to the JCPOA, the U.K., France and Germany – has been in contact with Iran several times in recent months and found strong indications that Iran wants to negotiate, Walters said.

Still, the ambassador added, “We’re not naive. We know they will want to draw [negotiations] out. We have told them very clearly that there is a deadline for doing a deal, and that deadline is in the middle of the year, the end of June.” 

Walters explained that the late June deadline would allow for the E3 to prepare to implement “snapback sanctions,” a mechanism in the JCPOA that would reapply sanctions on Iran, which Europe has hesitated to implement despite Iran’s continued violations of the deal since the U.S. pulled out of it in 2018. The first Trump administration attempted to activate snapback sanctions in 2020, but the other parties to the JCPOA said Washington forfeited that capability when it left the deal.

While Trump has reinstated the U.S.’ “maximum pressure” sanctions campaign on Iran in recent weeks, snapback sanctions would apply to all U.N. member states.

“October is the point at which the snapback mechanism expires,” Walters said. “If you wish to use snapback, you have to start the process well before October. We would need to start the process in the middle of the summer.” 

Walters emphasized that “the role that the E3 plays, our ability, uniquely, to trigger the snapback mechanism makes Europe’s role extremely important.” 

The ambassador said that the negotiations would not focus on improving the JCPOA, but to discuss “a totally different sort of deal, a deal which gives a complete guarantee that Iran is not going to develop a nuclear weapon.”

“When the situation changes, you change your approach,” he added. “We are in a different world now, and we need a deal that gives long-term confidence that Iran will not become a nuclear power.” 

Former U.S. Ambassador to Israel Dan Shapiro, who served as deputy assistant secretary of defense for the Middle East in the Biden administration, said that “the moment of truth,” when Trump and Israeli Prime Minister Benjamin Netanyahu need to make a decision about striking Iran, may come as soon as this fall if Iran leaves the Non-Proliferation Treaty or comes close to nuclear breakout.

“Iran is at its weakest point in decades, largely due to actions taken by the Israeli military against Hamas and Hezbollah, as well as a joint effort with CENTCOM, the United States, and Israel,” Shapiro said. 

While Shapiro said he believes the likelihood of reaching a diplomatic agreement with Iran is low, he asserted that it would only happen if Tehran believes that there is a credible military threat to it.

“A credible military threat is only credible if you’re prepared to use it,” he noted.

“If President Trump listens to voices in the administration who say we don’t need to have troops in Syria and we don’t need to have troops in Iraq … Iran will not take very seriously the threat of a strike because it says we want less involvement,” Shapiro said. 

The U.S. could make a military threat look more credible, Shapiro said, by deepening military cooperation with Israel, including joint exercises, and moving to protect U.S. military bases in the Gulf.

“Iranians would see all that preparation going on – we would do it to protect ourselves, but also to signal that we are serious about the military option,” he said. “This can all take place in the next four, five, six months while there are negotiations.” 

Shapiro also warned that it is not realistic for Israel to attack Iran on its own if the window for an attack on Iran’s nuclear program is in the next six to nine months, because of American bureaucratic procedures needed to provide Israel with the capabilities it does not have and the time it takes to train Israeli forces to use the weapons.