Some in Israel and the U.S. have questioned whether it's already too late for an Israeli strike to make a difference, as they did when Israel was able to make single-location attacks in Iraq and Syria. Several Iranian facilities are built so deeply they are potentially out of reach of even the biggest American "bunker-buster" bombs.
Israel's military lacks the size, breadth and weaponry needed for the kind of sustained, multi-pronged bombing campaign that could set Iran's program back by more than a year or two, experts say.
"Americans have the capabilities for carrying out a series of attacks," said Ephraim Kam, deputy director of the Institute for National Security Studies in Tel Aviv. "Israel might be capable of staging one strike."
Israeli officials, however, caution against underestimating their military's reach. Vice Prime Minister Moshe Yaalon told the 2012 Herzliya public policy conference Thursday that Israel was confident that "any facility in Iran can be hit, and I speak from experience as the [former Israel Defense Forces] chief of staff."
Yaalon said it was still possible that the Iranian regime would back down voluntarily, but only if leaders believed the government's survival were at risk. He said the only time Tehran has suspended its nuclear program was in 2003, when it was concerned that the U.S. might invade, as it had in Afghanistan and Iraq.
"If this regime faces this dilemma, it will be rational," Yaalon said. But the international community needs to demonstrate greater resolve, he added.
"The West has the ability to attack, but as long as Iran isn't convinced about their determination to carry it out, they will continue their manipulations."
Batsheva Sobelman in The Times' Jerusalem bureau and Kathleen Hennessey in the Washington bureau contributed to this report.