Garvan Walshe is a former National and International Security Policy Adviser to the Conservative Party. He now runs Brexit Analytics.

What to make of the mysterious news that Saad Hariri, the Prime Minister of Lebanon, announced his resignation – not from his office, but from abroad, in Saudi Arabia, the country in which his father had made his fortune, and which had so long backed his anti-Syrian and later anti-Iranian faction in Lebanon’s indefatigably complex politics?

The first instinct was that he had somehow been forced to leave the country by an increasingly assertive Hezbollah. Buoyed by its experience and success protecting the Assad regime in Syria, the Iran-backed militia would have seized their moment of power to push their sectarian rival aside.

But first instincts can be mistaken. This seemed hard to square with Hariri´s recent meeting with Ali Akbar Velayati, a powerful confidant of Iran’s Supreme Leader.

Soon, a more elaborate conspiracy theory emerged: that Hariri had been summoned by Riyadh and was being held there against his will. A strange TV interview, in which he appeared uncharacteristically nervous for a man who had supposedly cast off the cares of office, only reinforced suspicions that something was afoot. His promises to return to Lebanon to resign in person (his resignation not being valid until he does so) “soon” did not clear things up.

Observers began to suspect another power play by Mohammed Bin Salman, the restless Saudi Crown Prince. Fresh from an “anti-corruption” purge in which senior members of the royal family, unable to escape after the private jet airport was closed, have been imprisoned in the Ritz Carlton, the prince looks to have embarked on another foreign adventure to complement his expensive military quagmire in Yemen.

Could he have decided to raise the temperature of conflict with Iran by extending open confrontation to Lebanon (Saudi has been in covert conflict with Iran and Syria since Saad Hariri’s father, Rafik, was assassinated on Damascus’s orders on Valentine’s Day in 2005)?

If this power play has an aim, it is surely to show that Iran – despite keeping Assad in power (with Russian help), supporting Shia rebels in Yemen, and exercising hegemony over the government in Baghdad – cannot have it all its own way.

As Julian Barnes-Dacey, Senior Policy Fellow at the European Council of Foreign relations, warned me, there is “real risk that the combination of domestic and foreign initiatives could lead to overextension with possibly destabilising consequences.”

But concern for stability is hardly one of bin Salman’s priorities. His temperament seems to be that of a revolutionary in a hurry. From his domestic economic transformation plans, his denouncing of the Saudi religious establishment’s role in promoting extreme Islam, his purge and shakedown of previously leading members of the royal family, to the war in Yemen, he appears determined to shake things up first and ask questions later. He believes this is time for change, and he’s had enough of experts who think they know better.

Undoubtedly, there is scope for Riyadh to apply more pressure on Lebanon. Most obviously, it could squeeze an economy already adjusting to millions of Syrian refugees. But this is one of those threats that only works as long as it isn’t followed through. Cutting off economic support could trigger resentment and weaken, rather than strengthen, the Saudis’ hand. To make its plan work, the kingdom needs a new, more reliable Lebanese ally, but one which does not yet seem to be too much in their pocket since Lebanon’s Prime Ministers are appointed by consensus. Perhaps the former head of Lebanon’s Internal Security Forces – and, until he resigned in protest at Hezbollah’s dominance, justice minister – Ashraf Rifi, might fit the bill. His support has been strongest in the predominantly Sunni city of Tripoli. Saudi patronage might be able to help him to extend it.

This ease with which it is possible to speculate, and the difficulty of saying anything definite, shows how volatile the situation has become.

Normally, one would expect the United States to calm things down, as the last thing Washington needs is a further headache in this region, of all regions. But the Trump administration scarcely has a foreign policy. Secretary of State Tillerson is content to allow the senior ranks of the State Department to thin out. As the young boy plays with matches, the fire brigade is off sick.

‘MbS’, as the Saudi crown prince is known, is in need of adult supervision. If he once had a Sir Humphrey to warn that his conduct is too “courageous” for his own good, he is no longer being listened to. Perhaps such a mandarin exists, but has been dispatched to rest up at the Ritz Carlton hotel.