This year, like last, the Syrian foreign minister Walid Al Muallem will make his way to New York to speak at the United Nations General Assembly. His boss Bashar Al Assad these days rarely leaves Damascus for anything less than an audience with Russian President Vladimir Putin. Last year Mr Al Muallem claimed the regime was close to a military victory over the “terrorists”. This year, he will no doubt claim that goal is almost accomplished.

Unfortunately, that is true, with only one major province, Idlib, still in rebel hands. Yet the fate of that province will be governed less by what happens in such international forums as the United Nations and more by messily fought, temporary alliances made on the ground.

This week Mr Al Muallem will be addressing some of the world's most powerful politicians and diplomats but in the lawless, Hobbesian world of the conflict, what they think will matter less than what the commanders of militant groups inside Idlib do. In a very real sense, the territorial integrity of Syria will depend more on the leadership of militant groups such as Hayat Tahrir Al Sham than the leaders of the United Nations General Assembly.

Nor is Syria the only Middle Eastern country where that is true. The American invasion of Iraq and the Arab uprisings are the twin rocks upon which the rule of law has been dashed across the countries of the Levant and beyond. In country after country, it is non-state actors, groups that in some cases don't even speak to the government, that wield disproportionate power.

At a moment when the majority of Arab leaders are in New York, at a forum which embodies the ideals of diplomacy and the rule of law, it is sobering that too many Middle Eastern countries are not in full control of their own territory.

Hayat Tahrir Al Sham, the largest militant group in Idlib, is certainly one of the most pivotal. After a Turkish-Russian deal to carve out a demilitarised zone in Idlib was announced last week, the group said it would hold internal discussions on whether to accept or reject it. That decision, which will be crucial to the future of Idlib and to the three million civilians who live there, will be announced in the coming days.

Pause to weigh the gravity of that, and how far away the reality in Syria is from the lofty goals that will be espoused in New York. At the exact same moment that the leaders of the international community gather, the fate of millions of unarmed civilians on the shores of the Mediterranean might be decided, not by any legitimate government but by the decisions of a terror group.

Worse, the shifting sands of the Syrian conflict have allowed other countries to get involved, creating actions and reactions. Both the Iranians and the Israelis have used the chance to enter the fray, leading to the situation – as America's combative national security adviser John Bolton said in New York yesterday – where Russia will offer Damascus advanced weapons systems and the US will keep its troops on Syrian territory for the long-term.

All these actions have compounded the uncertainty of neighbours. Instead of being able to set policy in response to what Damascus does, the views of a range of powerful actors must now be taken into account.

The Russian supply of S-300s to the Syrian regime is a good example. The anti-aircraft system that Russia has promised is very effective; at a stroke it would halt the ability of Israeli fighter jets to encroach on Syrian territory, a prospect that terrifies Tel Aviv, which is why the US has come out so strongly against it.

It will most likely not happen – Russia, after all, has been promising to supply the system for the past five years – not chiefly because of US opposition, but because Moscow prefers to keep the regime reliant on its military protection.

Nor are Hayat Tahrir Al Sham the only ones. In Lebanon, there is Hezbollah, a militia that rivals the Lebanese state army and yet is beyond its control. In Yemen, there are the Houthis, who have torn the country apart by their desire to govern and yet would not even show up for peace talks organised by the UN in Geneva. In Iraq, a constellation of militias, some backed by Iran, exert enormous power beyond the reach of the central government, even in major cities like Basra.

All these groups have taken advantage of a weakness in their host states, using military and political means to gain influence.

No wonder then that, as the UAE's Minister of State for Foreign Affairs Anwar Gargash told The National, the Arab world lacks “consensus”.

Too many pivotal countries in the Middle East are not in full control of their own territory or, as with Hezbollah in Lebanon and the Shia militias in Iraq, the central government is unable to freely determine its own policies and has to take the views of other groups into account.

The disconnect between the ideals of the institution of UNGA – the idea that there is such a thing as international law and that relations between states should be governed by diplomacy – and the reality in the Middle East will be glaring this week.

That disconnect is compounded because no Middle Eastern country wants to undermine UNGA. For some big countries – Russia foremost among them, but at times other nations too – undermining the international rule of law and its institutions is a strategic goal, because it allows them to act unimpeded, using their military strength to get their way.

But it is probably true to say that there is no Middle Eastern country that feels that way (Libya's Muammar Qaddafi no longer being with us). The governments of countries – from Iraq to Yemen and Lebanon – want to operate under the framework of international rules, but circumstances have stopped them.

That should worry those gathered in New York. The theme of this year's general assembly is making the UN relevant to all, with a focus on “shared responsibilities” for peaceful societies. Those shared responsibilities do not end at the gates of the United Nations on the East River. The rule of law can only be as strong as its weakest links.