One lesson of history is that peace plans are forged by the victors. Almost exactly a year after the fall of Aleppo, the last urban stronghold of the Syrian opposition, peace-making diplomacy is now making a tentative comeback. Talks, sponsored by the United Nations, are expected in Geneva this week. That is to be welcomed, even though hopes of a breakthrough are slim. Since 2012, numerous rounds of negotiations have come and gone, all essentially fruitless. All too often it was Russian vetoes that hampered effective UN action, including on accountability for chemical weapon use.

Syria’s opposition groups have reorganised their negotiating team, pressured by the fact that they are in the weaker position. The Syrian regime, which first said it would boycott talks if the opposition insisted on Bashar al-Assad’s removal, has said it will send a delegation on Wednesday. The UN envoy, Staffan de Mistura, says his job is to be an incorrigible optimist. But it will take more than optimism to address Syria’s multifaceted war, to end the suffering, to repair a broken country and to begin to seek justice for its millions of victims.

Fighting is far from over. In recent days, airstrikes against the rebel-held eastern Ghouta district near Damascus have killed dozens. The Assad regime is intent on reconquering every hectare of territory it lost after the 2011 popular uprising which called for democratic reform, and which the dictator responded to with massive use of force. Last month, the US-led international coalition against Islamic State took over Raqqa, the “capital” of the self-proclaimed “caliphate”, after a campaign of intense bombardment. But battles continue in Syria’s eastern desert, close to the Iraqi border. Rival pro-Iranian and pro-US forces compete for strategic landmarks. Syria’s endgame may or may not be approaching.

What is clear is that Russia has been calling most of the shots. Vladimir Putin’s military intervention – launched in 2015 to save Assad, in a joint effort with Iran – has given him the upper hand. He has capitalised on US miscalculation and the European reluctance to get more deeply involved. Beyond Donald Trump’s threats against Iran, US policies remain murky – focused on little more than anti-terrorism. Last week, Mr Putin hosted talks in Sochi with the leaders of Iran and Turkey. And he appeared before the cameras with Mr Assad. Earlier this year Russia organised talks with Syrian opposition groups in Astana, Kazakhstan. It is a sign of a changing global landscape that at every step, both the UN and western powers were sidelined.

What has now changed? After years when Moscow either shunned or impeded any UN involvement, it is likely that Mr Putin now wants UN backing in order to cement its gains. Russia has a cynical interest in seeking UN validation for its plans. Continuous warfare drains resources. Rebuilding Syria will require a level of finances that Russia alone cannot secure. Relations between Russia, Turkey and Iran are less clearcut than their leaders would like to project. The Kurdish issue remains highly contentious. Against that backdrop, western countries, including the UK, believe they can still have some leverage on the outcome. It is a narrow and difficult path. No one should be fooled that promises of, say, “free elections”, cast as part of a Russian-dominated plan, would be anything but window dressing.

The six-year-old war has turned Syria into a wasteland. The words of the Roman historian Tacitus about “creating a desert and calling it peace” come to mind. An end to the terrible litany of airstrikes, starvation sieges and torture chambers cannot come a day too soon. But to talk of “victory”, as Mr Assad does, defies all sense of decency. There can be no victors in this war. Not after an estimated half a million deaths, with millions more displaced. Sustainable peace will only come when all Syrians have the chance to freely choose by whom and how their country is governed. That – and not pictures of summitry – should be the measure by which diplomacy is ultimately judged.