An aloof U.S. leaves a regional vacuum that the Islamic Republic is exploiting brilliantly.

By Reuel Marc Gerecht and Ray Takeyh

The Wall Street Journal

Iran has secured great-power patronage for the first time in four decades. Tehran now possess advanced centrifuges, a growing stockpile of highly enriched uranium, and a cadre of decent physicists and nuclear engineers. The clerical regime likely has no significant technical hurdle left to clear on its way to a nuclear weapon. Iran’s developing alliances with Russia and China have aided its atomic progress.

During Barack Obama’s presidency, as Iran’s nuclear program gained speed, the U.S. and Europe piled on sanctions, sometimes with the approbation of China and Russia. Today, geopolitics—as well as realpolitik nuclear calculations—are much friendlier to the Islamic Republic. Russia’s invasion of Ukraine made it crystal clear that Vladimir Putin doesn’t care for a world order led by Europe and the U.S. China, too, has retreated from being “a responsible stakeholder” in a liberal trading system. Instead it is trying to construct its own version of an East Asia Co-Prosperity Sphere, much of it designed to give Beijing dominion over Taiwan.

This revisionist alliance has ended Iran’s strategic loneliness. Russia, China and Iran all want to diminish American power. They recognize that they need to help each other militarily and economically to achieve common goals. This is why the Islamic Republic has supplied drone technology and artillery shells to Russia for use in a conflict that, at first glance, has no revolutionary Islamic interests. It is becoming increasingly hard to believe that Russia, which appears ready to deliver advanced Sukhoi Su-35 fighters and more sophisticated air-defense systems to Iran, is averse to sharing nuclear expertise and technology with the clerical regime—assuming Tehran is lacking something in its nuclear engineering.

For far too long, the Western foreign-policy establishment has gained comfort from the notion that Russia and China didn’t want a nuclear Iran. But Vladimir Putin would have no objections to a nuclear crisis in the Middle East if it diverted attention from his war in Ukraine. Unlike the U.S., Russia has lived with nuclear-armed states on its periphery for decades. The only thing new about an Iranian bomb would be the convulsive shock it would deliver to U.S. interests in the Middle East and beyond. For 20 years, American administrations have insisted that Iran would never be allowed to go nuclear. When it does, what’s left of America’s writ in the Middle East will evaporate.

China’s need for Middle Eastern oil has also roiled the region. Xi Jinping has shown few signs that he has any problem with Mr. Putin’s war to absorb Ukraine, which destabilized China’s second-largest trading partner, the European Union. Just before his invasion, Mr. Putin visited Mr. Xi and then proceeded with his assault.

An Iranian bomb could hasten U.S. withdrawal from the Middle East. The American political class has been allergic to the idea of military strikes against the clerical regime’s nuclear sites. It isn’t hard to envision them rationalizing that an Iranian bomb means little to the overall balance of power. A growing conventional wisdom in Washington counsels a shift of focus to Asia.

Saudi Crown Prince Mohammed bin Salman may be an impetuous, brutal man, but he made a sensible calculation with his recent Chinese-brokered compact with Tehran. He understands that the clerical regime is about to go nuclear and is trying to make amends with Iran’s friends—the mass murderer of Sunni Muslims in Syria and the Palestinian rejectionists. The minuscule Gulf principalities, always inclined toward appeasement, will probably follow with their own concessions. Without the U.S., the Middle East is sorting itself out.

In all of this maneuvering, Supreme Leader Ali Khamenei stands out. A man of humble origins who rose through the Islamic Republic’s eat-the-weak political system, he has steered his country through a gantlet of lethal enemies. When he remarked recently that “the U.S. wanted to put an end to the nuclear issue in accordance with its own plans of using the pressure of sanctions, but it failed” he was being, as he often is, coldly factual. Iran’s never-ending internal troubles may yet unseat him and his regime, but the cleric has done what only great rulers do: He has taken a weak hand and played it brilliantly.

Mr. Gerecht, a former Iranian-targets officer in the Central Intelligence Agency, is a resident scholar at the Foundation for Defense of Democracies. Mr. Takeyh is a senior fellow at the Council on Foreign Relations.