t’s a scene that’s been played out both in high drama and a blockbuster thriller, in Death and the Maiden and in Marathon Man – a victim chancing many years later upon their tormentor – but in Berlin in 2014 it happened for real. Anwar al-Bunni was in a grocery shop when he ran into a fellow Syrian émigré whose face was familiar. It took him a while to realise that the man was a former intelligence officer who, al-Bunni was sure, once interrogated and jailed him. That encounter led to a trial in a Koblenz court of both that officer and an underling, and this week the more junior of the pair, Eyad al-Gharib, was found guilty of aiding and abetting a crime against humanity inside one of Bashar al-Assad’s jails, a crime that included torture. The verdict was hailed as a first encouraging crack in the impunity of the Assad regime, which has not yet faced justice for the hundreds of thousands of Syrians it killed as it suppressed an uprising that began a decade ago. Optimists detect a pattern. In Washington on Friday, Joe Biden decided to release a CIA report, long blocked by Donald Trump, implicating Saudi Arabia’s crown prince, Mohammed bin Salman, the country’s de facto ruler, in the murder of Jamal Khashoggi, the dissident journalist whose body was hacked to pieces by a bone-saw. Biden has signalled that he won’t deal directly at all with the crown prince, who was a chum of the Trump White House. He has also ended US backing for Riyadh’s repugnant war in Yemen, the prime cause of what the UN calls the world’s worst humanitarian crisis; and he’s frozen a major US-Saudi arms deal. Elsewhere, the international criminal court (ICC) this month ruled that it can investigate Israel and Hamas over alleged war crimes in the West Bank and Gaza, while the international court of justice, which prosecutes states rather than individuals, is weighing genocide claims against Myanmar for its persecution of Rohingya Muslims. Taken together, it can look like a hopeful rebuttal of the case made by the former foreign secretary David Miliband: that we live in a new “age of impunity”. The optimists can also cite growing acceptance of the principle of universal jurisdiction, which allows for any court to pursue serious crimes committed anywhere, and which might explain why the likes of George W Bush and Donald Rumsfeld these days tread only warily outside the US, for fear of facing torture charges for the practice of waterboarding. But then you remember that the man convicted in Koblenz was small fry, that Assad’s ruling circle, and the dictator himself, remain untouched despite being drenched in the blood of their fellow Syrians. (Don’t be distracted by Biden’s airstrikes on Syria on Thursday night: their target was Iranian-backed fighters, after attacks on US forces in Iraq, and had nothing to do with punishing Assad.) And this week the former war crimes prosecutor Stephen Rapp said that the evidence of murder, torture, mutilation, rape and other forms of sexual violence directly ordered by the Assad regime was so strong that it was “even better than [the evidence] we had against the Nazis at Nuremberg, because the Nazis didn’t actually take individual pictures of each of their victims with identifying information on them”. And yet, there is no ICC case against Assad: Syria never signed up, so the court has no jurisdiction over it. Next you contemplate an ongoing crime whose scale and cruelty can make the soul sink. The Chinese state’s war on the Uighur Muslims is also amply documented: the depths of depravity – and the bleak historical echoes – confirmed month after month. If you’re not shocked by the evidence of a forced sterilisation programme, designed to prevent there being a next generation of Uighur people, perhaps it will be the sight of 13 tonnes of human hair, suspected to have been shaved from the heads of women kept in a detention camp and packaged for sale as hair extensions abroad. If it’s not the raw numbers, of at least a million Uighur people incarcerated for “re-education” so that their distinct Muslim culture and identity might be forcibly purged from them, then maybe it will be the footage of Uighur men loaded on to trains, to be transferred to distant camps. Once again, though, there’s no ICC case against China’s rulers for this wickedness. The ICC confirmed in December that because China is not signed up, the Uighurs fall outside its scope. It seems a kind of madness that the very countries guilty of outrageous atrocities can escape justice simply by opting out of the court set up to prevent and punish them. Exceptions can apply if, for example, an alleged crime is committed in a territory that does recognise the court, which is why the ICC has been able to open files against Israel and the US. Otherwise, it takes a resolution of the UN security council, almost impossible given that the big powers tend to veto any prosecution of themselves or a favoured ally. It means Miliband’s talk of an age of impunity looks more accurate than the optimists might like. The only quibble would be whether it’s new. Even the much-vaunted, postwar Nuremberg trials caught only a handful of the perpetrators of the Holocaust: most of the killers got away with it. It suggests a grim conclusion: that apart from a symbolic win here and there, the most appalling cruelties go unpunished. And will keep going unpunished. The writer and international lawyer Philippe Sands, who is acting in the Myanmar case, is more philosophical. “It’s a long game and we’re right at the beginning,” he says. Yes, nation states still cling jealously to the notion of sovereignty. And yes, after the conceptual breakthrough of Nuremberg, the cold war ensured nothing happened for 50 years, until there was action on Rwanda and Serbia in the 1990s. But, bit by bit, there is a steady chipping away at impunity. The pace is glacial, he concedes. How slow? “It’s a 400-year project.” It seems a long time to wait. One move that would help, says Sands, is to stop regarding genocide as the sole unconscionable crime, and to put greater emphasis on the broader category of crimes against humanity by supporting the draft treaty now stuck at the UN. He suspects the UK government is wary of making that move, not least because it risks being called to account for its own crimes, including the refusal to allow the people of the Chagos Islands to return to their homes, following two international court rulings. But the law is not our only weapon. There are other sanctions – social and cultural – that are available. In a week when China has been praising itself for its poverty numbers and its global vaccination efforts, and as it prepares to host next year’s Winter Olympics, it should be reminded at every turn of the evil it is wreaking upon the Uighurs. Some in the west hesitate to speak out, fearing the accusation of hypocrisy because our own countries are not perfect. That impulse delights the likes of Assad and the Chinese Communist party. It means we keep our mouths shut. But our silence helps no one – least of all those who cannot speak for themselves. • Jonathan Freedland is a Guardian columnist