Washington and Tehran may currently be close to concluding an updated version of the 2015 nuclear deal, although it is unclear if diplomats will be able to resolve the remaining points of contention. If they succeed in doing so, Beijing—which has been growing ever closer to the Islamic Republic in recent years—stands to benefit, as Craig Singelton explains:

Years of punishing international sanctions have left Iran diplomatically and economically isolated, with Tehran seeking greater support from other autocratic regimes. That extends to its partnership with China, which in recent years has become Iran’s top trading partner, a leading destination for energy exports, and a major investor in Iranian industry. While Sino-Iranian military cooperation has ebbed from its heyday in the 1980s and 1990s, the two countries engage in periodic military exchanges, joint exercises, and port calls. In January, for example, eleven Iranian vessels joined three Russian ships and two Chinese vessels in a series of joint tactical and artillery drills in the northern Indian Ocean. Likewise, China actively supports Iran’s cruise- and ballistic-missile programs, providing it with technology that has been integrated into systems used against U.S. forces in neighboring Iraq as recently as 2020.

Yet, Singleton notes, China has also set limits on its cooperation with the Islamic Republic, no doubt because of the possible negative effects of U.S. and European sanctions. A nuclear deal would change that:

Free from the threat of sanctions, China will almost certainly ramp up its investments in and trade with Iran, deepening not only its influence there but in the region as well. . . . China will also expand its reach throughout Iran’s steel, gold, and aluminum sectors, having previously invested in other materials-processing projects that enabled Iran to produce inputs for its missile program.

The same applies to infrastructure and transportation-related projects aimed at connecting Iran to China’s regional networks in South and Central Asia. That includes a planned train route between Iran and China’s Xinjiang province, where the United Nations recently determined Beijing is committing “serious human-rights violations,” such as forced labor and sterilizations. Tehran will also lean on Beijing to modernize its telecommunications architecture, including requesting assistance in installing the same artificial-intelligence surveillance technology that China has exported to other autocratic regimes. The result will be even more censorship and political repression for millions of Iranians.

Last Sunday marked the eighth anniversary of a Saudi-led alliance’s intervention in the Yemeni civil war, intended to defeat the Iran-backed Houthi militia that had overthrown the previous government. In the wake of the rapprochement between Riyadh and Tehran, diplomats are hoping that the talks between the Saudis and the Houthis—which have been ongoing since last summer—will finally succeed in ending the war. To Nadwa Al-Dawsari, such an outcome seems highly unlikely:

The Houthis’ military gains have allowed them to dictate the path of international diplomacy in Yemen. They know Saudi Arabia is desperate to extricate itself and the international community wants the Yemen problem to go away. They do not recognize and refuse to negotiate with the [Riyadh-supported] Presidential Leadership Council or other Yemeni factions that they cast as “Saudi mercenaries.”

Indeed, even as the Houthis were making progress in talks with the Saudis, the rebel group continued to expand its recruitment, mobilization, and stockpiling of arms during last year’s truce as Iran significantly increased its weapons shipments. The group also carried out a series of attacks. . . . On March 23, the Houthis conducted a military drill close to the Saudi border to remind the Saudis of “the cost of no agreement and further concessions.”

The Houthis are still part and parcel of Iran’s so-called “axis of resistance.” With the Houthis gaining international political recognition, . . . Iran will have a greater chance to expand its influence in Yemen with the blessing of Western powers. The international community is eager for a “success story” in Yemen, even if that means a sham political settlement that will likely see the civil war continue. A deal with the Houthis is Saudi Arabia’s desperate plea to wash its hands of Yemen, but in the long term it could very well position Iran to threaten regional and international security. More importantly, it might set Yemen on a course of protracted conflict that will create vast ungoverned spaces.

Meanwhile, tensions in Yemen between Saudi Arabia and its ostensible ally, the United Arab Emirates, are rising, while the Houthis are developing the capability to launch missiles at Israel or to block a crucial Middle Eastern maritime chokepoint in the Red Sea.