President-elect Donald Trump will encounter an Iran that is suddenly far more brittle than it was during his first administration, its leadership more uncertain, its nuclear program more exposed and vulnerable to attack.

That new reality has touched off an internal debate about how his administration should approach Iran: with an openness to negotiations, or with an attack on its nuclear enrichment program — overt or covert, or perhaps initiated by Israel.

Or, as many suggest, a round of “coercive diplomacy” that leaves Iran to choose either a negotiated disassembly of its nuclear capability, or a forced one.

The urgency of the issue was underscored Sunday by Jake Sullivan, President Joe Biden’s national security adviser, who told Fareed Zakaria of CNN that with Iran’s main proxies weakened or eliminated, “it’s no wonder there are voices saying ‘Hey, maybe we need to go for a nuclear weapon right now.’”

He added that he had discussed the “real risk” of an Iranian race for the bomb with the Trump national security team and with the Israelis.

In interviews over the past two weeks, officials from the U.S. and other countries have said that the menacing dance over Iran’s nuclear future could take a dramatic turn in the next few months. That assessment came after the United Nations’ top nuclear inspector warned that Iran was accelerating its enrichment of near-bomb-grade uranium.

Iran’s new president, Masoud Pezeshkian, and Trump have voiced a willingness to negotiate a new nuclear deal, though neither has said a word about its terms.

But both men know that the military balance has shifted — and that Iran’s capability to strike back at Israel through its proxies, and even its own missile fleet, has been vastly diminished. So while the opportunity for diplomacy has not been greater in six years, neither has the possibility of a preemptive strike.

In public comments, Trump’s aides have promised a renewed “maximum pressure” campaign that concentrates on cutting off Iran’s oil revenue by leaning on China, the largest purchaser of sanctioned Iranian oil shipments.

“The change you’re going to see is more focus on Iran,” Michael Waltz, whom Trump has designated as his national security adviser, said in November on CNBC. “Maximum pressure, not only will it help stability in the Middle East, but it’ll help stability in the Russia-Ukraine theater as well, as Iran provides ballistic missiles and literally thousands and thousands of drones that are going into that theater.”

Sullivan did not discuss the specifics of his conversations with Israel. But current and former Israeli officials have publicly debated whether to seize the moment. Yoav Gallant, the Israeli defense minister whom Prime Minister Benjamin Netanyahu fired in early November after months of disagreements over how to respond to the Oct. 7, 2023, terror attacks, recently said there was “a window to act against Iran” before it can take the last few steps to producing a nuclear weapon.

Netanyahu told The Wall Street Journal last week that the Iranians “were dumbfounded when we took out their critical air defenses” on Oct. 26, in the final act of a second exchange of missile attacks between Iran and Israel.

“What’s different now is the Iranians are incredibly vulnerable,” said Eric Edelman, a former senior Defense Department official in the Bush administration. Edelman recently published an analysis calling on Trump to give Iran a negotiated way to surrender its nuclear material and win a lifting of sanctions or face a direct attack on its nuclear facilities.

“They now have coming to office a former president who they apparently tried to assassinate, and a prime minister in Israel who has every incentive to want to strike, partly to restore his own reputation,” he said.

“If, together, they really crank up the economic heat, the diplomatic pressure and the military backup, you will really test the proposition that you can end the nuclear program.”

A crisis Trump helped create

Trump, of course, is inheriting a nuclear buildup he helped create.

Iran’s program was frozen after the 2015 nuclear accord with the Obama administration. But Trump campaigned in 2016 on a platform that the Obama-era deal was a “disaster” — for reasons he had difficulty articulating in an interview — and in 2018 he pulled out of the accord and reimposed sanctions. He predicted that the Iranians would come begging for another deal, one more to his liking. They did not.

For two years the Iranians held back on resuming production, trying to negotiate a way around the sanctions with European powers. That effort collapsed, as did one by the Biden administration to see whether it could revive the abandoned accord with something “longer and stronger.”

A recent unclassified intelligence assessment provided to Congress concluded that Iran had enriched enough uranium to make upward of a dozen weapons since the United States pulled out of the deal.

Several weeks ago, Iran accelerated production of 60% enriched uranium, according to Rafael Grossi, the director general of the International Atomic Energy Agency. That is just short of the 90% enrichment used to make a bomb.

Secretary of State Antony Blinken said in July that Iran would probably just need “one or two weeks” to enrich to bomb-grade levels.

There is debate over what it would take to turn that fuel into metal and fashion it into a warhead. But a crude bomb — one delivered, say, on a freighter — might take only six or eight months. A more sophisticated one that fits atop a ballistic missile might take a year and a half.

The shape of a new deal

It is very possible that Trump will make a show early on of massing a military force designed to strike the Iranian facilities — and then enter a negotiation. It is an approach that Edelman and others call “coercive diplomacy.”

But striking a deal that goes beyond the Obama-era accord that Trump dismissed as useless would be difficult. The 2015 accord got 97% of Iran’s enriched uranium out of the country — the Russians took it, for a fee — and delayed for years Iran’s ability to install a new generation of highly efficient centrifuges, the giant machines that spin at supersonic speed to enrich uranium. Trump’s decision to pull out of the accord gave Iran an excuse to install the new machines earlier than they had agreed.

Any new agreement would almost certainly have to require Iran to turn over all of its enriched uranium and all of those centrifuges, and to allow international inspectors into every suspected facility where new equipment could be produced.

That is a level of dismantlement and transparency that Obama officials could not win during several years of negotiations.

Trump’s history suggests, as Waltz noted, that he will start with renewed economic sanctions, though they have a poor track record of effectiveness.

“The ‘perfect pressure’ campaign must squeeze Iran further, particularly by cutting Iran’s oil revenue,” Beth Sanner, Trump’s CIA briefer during part of his first term, wrote recently. “This means going after the shadow fleet that moves the oil.”

But the essence of coercive diplomacy is the underlying message to Iran that one way or another — by diplomacy or force — it will have to give up the fuel stockpiles and capabilities that have put it on the threshold of a weapon.

Iran may be willing to make a tactical retreat, but it has never been willing to shut down all of its facilities. And it is unclear, at least for now, how much risk Trump is willing to take to achieve that goal.