The fight for Aleppo is at an end. The clusters of desperate Syrians who remain huddled in the last rebel redoubt face an imminent reckoning, to yield to loyalist forces across the nearby dividing line or to stay and face capture. Or to accept the terms of a last-minute deal that allows anyone left to flee.

Aleppo will be cleansed of the the anti-Assad opposition and anyone who sympathised with it. Those who do flee, or who win the mercy of the conquerors will face exile, likely in Idlib province, a bastion of the latest incarnation of the al-Qaida inspired Jabhat al-Nusra, which is prescribed as a terrorist group by all of the war’s protagonists.

Idlib will hardly be a refuge. After Aleppo, it will be the last urban stronghold – except for Isis-held Raqqa – outside regime control. Rebel communities from other defeated corners of Syria have already been sent there after regime victories, where they have continued to be bombed by Russian and Syrian jets.

The presence of jihadis offers the perfect pretext for the attacks to continue – their conflation with the rebels has been a constant theme of the regime narrative that it is fighting terrorist groups. Having them all mixed together serves such messaging usefully and portends poorly for the vanquished.

Assad’s claims that the fate of Aleppo will prove decisive in the war will probably be proved true. But the throes of victory obscure another, more enduring, truth: that stability will remain elusive for a long time to come. So too will a central tenet of Assad’s claim to continued leadership: sovereignty.

Assad has been helped into a winning position by Iran and Russia, who have done far more than his beleaguered military to all but defeat the opposition. Iran has had effective strategic control over how the war is run for the past three years. Militias from Lebanon and Iraq, which Tehran arms and organises, have been instrumental in overrunning eastern Aleppo, a goal that had remained well out of reach of Syrian forces since they were ousted from the city in mid-2012.

And from above, the scale and reach of Russian firepower has rained down on a city that has successfully sheltered insurrections throughout the ages. The devastation of eastern Aleppo is staggering. Think Hama in 1982, a massacre ordered by Assad’s late father, Hafez al-Assad, which killed an estimated 20,000 people, and which took place away from the world’s gaze.

In that sense, Aleppo is different; the suffering has been on regular display. It has been so long and agonising, and the international response so insipid, that many observers have been begging for it to end.

Assad has shown no sign that he will apply the mercy rule. And nor do his backers, who for different reasons appear determined to segue this win into an all-out victory across the country. This is where things will become problematic for the Syrian leader, who owes his continued presence in the presidential palace to Tehran and Moscow. Both powers will take a driving stake in what comes next and, while there has thus far been common ground for them in ensuring Assad survives and Syria keeps its territorial integrity, the next phase of the conflict will probably prove trickier for Assad to navigate.

Iran wants a postwar Syria that reinforces Damascus as a bridgehead for Hezbollah – an essential arm of its political military projection vis-à-vis Israel and the US. Iranian officials also claim their role in winning the war gives them more of a say in defining the national character of Syria, which they have been invested in since shortly after the Islamic revolution of 1979, though not on this scale.

A resurgent Russia is also sure to explore the spoils. Vladimir Putin has brought himself a say, and a base in the post-Arab Spring region through which he can project Russian influence. Russia is ascendant in the region, at the expense of the US, the influence of which friend and foe alike acknowledge has waned. None of this augurs well for those in the last ravaged corner of Aleppo, or hunkering down in Idlib, where the victors will certainly come for them.

The grievances that fuelled the conflict remain fundamentally unaddressed. Sunni disaffection is one important, and sometimes overriding factor. And, without a political process that addresses this, a military victory will not mean much in the long term.

The misery and uncertainty is entering a new phase. But it is not over yet.

Martin Chulov in Beirut