With Nuclear Deal Dead, Containing Iran Grows More Fraught

When Iran agreed to a deal in 2015 that would require it to surrender 97 percent of the uranium it could use to make nuclear bombs, Russia and China worked alongside the United States and Europe to get the pact done.

The Russians even took Iran’s nuclear fuel, for a hefty fee, prompting celebratory declarations that President Vladimir V. Putin could cooperate with the West on critical security issues and help constrain a disruptive regime in a volatile region.

A lot has changed in the subsequent nine years. China and Russia are now more aligned with Iran’s “Axis of Resistance” to an American-led order, along with the likes of North Korea. When President Biden gathered the leaders of six nations for a video call from the White House on Sunday to plot a common strategy for de-escalating the crisis between Israel and Iran, there was no chance of getting anyone from Beijing or Moscow on the screen.

The disappearance of that unified front is one of the many factors that make this moment seem “particularly dangerous,” said Vali Nasr, an Iranian-born professor at the Johns Hopkins School of Advanced International Studies, “maybe the most dangerous in decades.”

But it is hardly the only one.

President Donald J. Trump’s decision to pull out of the Obama-era nuclear deal triggered a predictable counterreaction from Tehran, and after a long pause, Iran resumed enriching uranium — some to near-bomb-grade quality. Today it is far closer to producing a bomb than it was when the accord was in effect.

Tehran has surged ahead with its ballistic missile program, and several months before some of those weapons were unleashed on Israel this weekend, all the remaining United Nations prohibitions expired. Iran has not only emerged as Russia’s most dependable foreign supplier of military drones, but it has also improved its own drone fleet by drawing lessons from their use in Russia’s assault on Ukraine.

President Barack Obama’s pursuit of the 2015 nuclear deal was assailed by many Republicans as dangerously irresponsible at the time. Even some Democrats, though supportive of the details of the deal, worried that Mr. Obama was naïve to hope it would bring about fundamental change in Tehran.

With the latest escalation of tensions between Iran and Israel, Mr. Biden’s political opponents are now blaming the administration for having not taken a tougher line in recent years against Iran. They say that has left Israel in particular peril at a moment when it is mired in a war against an Iranian client group, Hamas, in Gaza.

“The White House signaled both obliviousness and weakness by not recognizing that today’s Middle East conflict is not Palestinians or Arabs against Israel, but an Iranian war against ‘the little Satan,’” John R. Bolton, who served as national security adviser to Mr. Trump and was a sharp opponent of the Iran deal, wrote on Sunday.

“The sad truth is that Israeli and U.S. deterrence against Iran failed,” he…