In the Great Hall of the People in Beijing, Saudi Arabia's national security adviser, Musaad bin Mohammed Al Aiban, and Iran's Secretary-General of the National Security Council, Ali Shamkhani, face each other for a handshake and smile into the cameras. Between them a joyous Wang Yi, who had recently risen to become the new director of the Central Foreign Affairs Commission office. It was through his mediation that the agreement, which all three politicians had signed beforehand, was concluded - and thus, quite incidentally, a diplomatic respectable success for the People's Republic of China was achieved.

The agreement, which was discussed intensively by Iranian, Saudi and Chinese delegations in four days of negotiations from March 6 to 10, contains first and foremost one thing: a declaration of intent to resume diplomatic relations between the Islamic Republic of Iran and the Kingdom of Saudi Arabia and to reopen the embassies of both countries in Riyadh and Tehran within two months. This is a remarkable step, given that the two regional powers are bitter adversaries, each claiming leadership in the Gulf, the Middle East and the entire Islamic world, and confronting each other directly or through their proxies in all sources of conflict from Iraq to Yemen.

Iran and Saudi Arabia had severed diplomatic relations in 2016 after years of escalating confrontation. The March 10 declaration has the potential to be not just a political declaration of intent for a better understanding, but a game changer for the region in contexts such as Lebanon, Iraq and Syria. In the region's second major conflict, the Yemen war, the resumption of diplomatic relations opens up the prospect of peace between Riyadh and the Houthi militia for the first time in eight years.

But the most important and potentially far-reaching impact of the trilateral declaration may be China's growing role and increased political clout in the Gulf. Beijing was able to skillfully use the vacuum left by a distracted U.S. to position itself as a mediator. The Arab-Chinese summit in Riyadh in December 2022 was a first taste of the People's Republic's strategic ambitions in the region, as it seeks not only to be a trading partner and investor but to prove that it is ready to assume foreign policy responsibilities in the Gulf. With a planned summit between the Gulf Cooperation Council states and Iran in Beijing this year, China now wants to solidify its new role as an alternative to the 'old' regulatory power, the United States.

Chances are therefore good that Iran, given Chinese influence and China's closer ties with Saudi Arabia, will now be forced to implement even the difficult pledges of the Beijing agreement. That includes the Iranian promise to stop Houthi attacks on Saudi territory, which Beijing had wrested from Tehran. It is noteworthy that China is currently the only actor that can put pressure on Iran to implement such promises, and whose security assurances are simultaneously accepted by Saudi Arabia. Thus, the People's Republic suddenly finds itself in a role as conflict mediator and guarantor that its regional policy in the Middle East, which was purely geared toward economic exchange, had apparently never sought. Ultimately, the implementation of the trilateral declaration in the coming months will be a litmus test for how far Beijing's influence in the Gulf actually goes.