The Middle East has always been an arena in which you can assess the changing dynamics of the Great Powers. When the sun never set on Britain’s empire, that was the region where it did some of its most extensive — some would say destructive — work. When the mantle of world dominance passed to the United States, that was where we saw sustained intervention.

Now, with Washington turning its colossal tanker toward Asia, another power — ironically, the one the Americans most fear — may be stepping into what is starting to look like a void. Jerusalem has long been concerned about a US retreat from the region, and it seems such fears are in danger of being realised.

Last week, Riyadh, the Sunni Lion, and Tehran, the world’s largest and most powerful Shia state, signed a deal negotiated by China. A joint statement declared that the two countries had agreed “to resume diplomatic relations and reopen their embassies” within two months, promising not to interfere in each other’s “internal affairs”.

The story here is both a macro and micro one. At the macro level, it is about China’s changing view of itself in the world. Under the country’s previous leader, Hu Jintao, among Beijing’s key foreign policy principles were “building and accepting a world where countries diverge in their paths of national development and political systems”, rejecting “unilateralism and hegemonic ambitions.”

Xi Jinping has different ideas. Throughout the first 20-odd years of turbulence in the region, China has, legally speaking, been a passive player. It has economic interests, not least as a consumer of both Iranian and Saudi oil. A sustained flow from the Gulf to Asia is key to its strategic interests. Otherwise, its involvement has been relatively limited, particularly in the political sphere.

Now, though, it is stepping up to play a more muscular role. According to the analyst Jonathan Spyer, the most notable aspect of this deal is that it represents the arrival of China to the Middle East diplomacy stage.

“This will remain the case whether or not the deal ultimately proves durable and fruitful,” he argues. “Until now, Beijing’s consistent position was that it sought to build commercial links with Mid-Eastern countries while avoiding involvement in its geopolitics. That has now changed, and the change is of deep significance.”

What is more disconcerting is that Riyadh — as well as the other Gulf monarchies — has concluded that Washington no longer has a coherent strategy in the Middle East, beyond the desire to avoid further lengthy entanglements, the “forever wars” that Trump railed against.

“The option of sheltering within a clear and durable US-led security architecture in the region did not appear available,” Spyer says.

“Riyadh urgently needs to concentrate on internal matters related to its transition from a petro-chemicals based economy. The option of Beijing-led rapprochement with Tehran appeared to offer a road to this… Hence the deal.”

These desires have had greater urgency given Joe Biden’s decision — marking a clear change in US policy — to restrict arms sales to Saudi Arabia over its use of air power in the Yemen war.

Iran also has an interest in engaging with Beijing. A long-standing international pariah, its continuing crackdown on its own citizens has cemented its rogue status. And with Obama’s nuclear deal a distant memory, the Iranians need new allies, the more powerful the better.

Amid all of this of course stands Israel. To complicate things further, while it is unlikely to be imminent, Riyadh may yet join the Abraham Accords. Earlier this month, the Washington Post reported that the Saudis had asked the United States for security guarantees and a civilian nuclear programme as the price of signing up.

From Jerusalem’s standpoint, a Saudi-Iranian rapprochement remains unlikely to happen any time soon. It is important to understand what the deal does — and does not — represent. The Saudis aren’t about to join an alliance with Iran against Israel. They are merely hedging their bets. In 2023, it’s clear that the Middle East is no more stable than it was 20 years ago, before the 2003 US-led invasion of Iraq. States on all sides are struggling to understand who will emerge as the new superpower in the region, and how they should act in response.

The US has made clear that it wants to pivot toward Asia and to take on the Chinese threat. But it may soon have to face down the same foe in its old battleground, the Middle East. For Israel, that may best happen sooner rather than later.