In the run-up to Donald Trump's first overseas visit, it was widely trailed that he would endorse an “Arab Nato”, a military alliance to defend the Middle East from internal and external threats.
In the end, his extensive speech did not mention the words Arab Nato at all, but the combination of his firm position against Iran, the billions of dollars in arms sales to the region, and his exhortation for the Middle East not to wait “for American power to crush this enemy for them” were taken as confirmation that this military alliance will happen.
Unsurprisingly, the Middle East has been here before. In the 1950s, it was Britain that sought to bring together a military alliance against a major threat. Iraq, Iran, Turkey and Pakistan formed what was known as the Baghdad Pact.
Half a century on, the “Riyadh Pact”, like the Baghdad Pact before it, is aimed at internal and external enemies. With the Baghdad Pact, the British were seeking to build an alliance against Soviet interference in the Middle East. But they were also looking for a way to contain rising Arab nationalism.
The Riyadh Pact is similar. There is an external aggressor, Iran, and an internal one, Islamist extremism, and the group will target both. How far the Middle East has changed in 60 years, that one of the principal members of the Baghdad Pact is now the enemy of the Riyadh Pact. But, again, the two are linked, because it was the 1979 revolution in Iran that brought about the collapse of the Baghdad Pact – just as it brought to power an expansionist ideology in Iran.
Then, as now, the main challenge to an Arab Nato isn't logistical, but political. How will the countries that form the alliance – Saudi Arabia, Egypt, the UAE, Jordan and, perhaps, Pakistan – cope with the political challenges? Who will command the army and what will the decision-making process be? Will a country have to take part even if it disagrees with the mission?
There are other important questions, related to how any treaty of the organisation is formed. Take, for example, Nato's Article 5, the provision that an attack on one member is an attack on all. This is the cornerstone of the North Atlantic collective defence posture. Would an Arab Nato have a similar provision and, if so, would that mean Egypt could be dragged to Pakistan's defence in the event of a war with India?
Or take Chapter 7 of the United Nations charter, which authorises the Security Council to involve itself in a breach of peace within member countries. A provision like this could mean Saudi and Pakistani troops inside Jordan if, for example, ISIL or a related group held territory there. If more Arab countries join, the politics become further complicated.
What would happen if, at some point, Turkey joined? From one perspective, this would make sense: Turkey is a large Sunni country joining an alliance of predominantly Sunni states. And Turkey is already a member of Nato.
But Turkey's sheer size and complex political environment create complications of their own. In 2012, after Syria shot down a Turkish jet, Ankara invoked a Nato article that gathered the alliance together to discuss a response. Would it also gather its Arab allies? That would be a formidable coalition.
The relationship with Nato is also interesting. The UAE has contributed to Nato missions in Bosnia, Libya and Afghanistan. It was an observer at the past two Nato summits, and has taken part, along with other Gulf states, in military exercises with the alliance.
Whereas the Baghdad Pact was a military alliance that was envisaged to operate only within the region, the logic of an Arab Nato is that it would, eventually, operate beyond it. Given the close links that already exist, it is conceivable that an Arab Nato would take on a role somewhere in the world alongside Nato itself. From that small step, it follows that an Arab Nato could conduct peacekeeping operations beyond the Middle East.
All of which is to note the gravity of a genuine military alliance. It would change the political posture and foreign policy of the countries involved.
None of this would be apparent immediately. The Riyadh Pact has been formed to fight two enemies, ISIL and Iran. The first of those is easier to deal with, despite being amorphous. But the real test for an Arab Nato would come on the day after Raqqa falls.
Because while a real war with Iran is still unlikely – the military might of the Gulf and the presence of US warships in the region mean that any attack would be easily repulsed – the longer-term danger is that Iran continues its policy of destabilisation. By continuing to support regimes and rebels around the region, Tehran has created a significant amount of chaos, while stopping short of fighting an unwinnable war.
An Arab Nato would have to grapple with that precise challenge, as Nato, in similar circumstances, has had to do with Russia. In both cases, the weaker foe has picked at the edges of the alliance, never provoking enough for a real war. Even faced with a united military alliance, Tehran will probably continue that strategy. A military alliance, then, is not the end of the rivalry between Saudi Arabia and Iran, but the enabler of a more formidable defensive posture that allows cooler heads to prevail.
Pushing back Iranian influence will need both military might and clever politics. The Riyadh Pact is the big stick that enables softer speech.
On Twitter: @FaisalAlYafai