Why now? That’s the question. Why now, after 19 months of relentless assault that was plain for all to see, and declared by Israeli authorities themselves, has the tide begun to shift on Gaza?

The marked change in tone this past week from leaders in the UK and EU is a clear break from the pabulum of “concerns” and reiterations of Israel’s right to defend itself. Now the rhetoric is that Israel’s actions are “morally unjustifiable” and “wholly disportionate”, and the threats of its leaders “abhorrent”. Some of this is future-proofing. The war has amounted to genocide and ethnic cleansing in ways that are increasingly undeniable, indefensible and unspinnable. Some had a good go at it for a year and a half, but now cannot stand at a lectern or sit at a dinner table and argue that, yes, actually, there is an argument for killing 100 people a day, as was the case last week. Or that Israel has any plan other than what its leaders have consistently declared to be one of displacement and settlement. Long gone is the argument that this is simply about wiping out Hamas. Israel, as one British media ally lamented, has hung its friends out to dry.

But there is a disconnect between condemnation and outrage, and what happens on the ground. When it comes to Israel, the levers of international censure are broken. Throughout the war, international organisations, humanitarian missions and courts of justice have been rendered powerless by their inability to translate their findings into action. Words alone mean nothing. They simply bounce off Israel’s iron dome of impunity. Every day, the world wakes up and is confronted with an Israeli leadership that violates every law of morality and logic. Victims are aggressors, humanitarians are biased, an army that kills unarmed medics is the most moral army in the world. Up is down.

The recent change in language from Israel’s international allies is remarkable. But it would be dangerous to overestimate its significance. Israeli authorities not only do not care, but draw strength from the condemnation. It all serves to prove that the country is on its own and must persevere because it is, as ever, misunderstood, discriminated against, surrounded by enemies. The shift feels like a breakthrough only in comparison to what came before. For so long, the act of calling what is happening in Gaza by its name has been traduced, even criminalised. There are people sitting in detention for the charge of describing reality. If anything, the past year and a half has seen a series of breakthroughs that signified nothing; historic protests, a sea change in global public opinion, a tussle at the heart of western political, legal and academic institutions over the right to protest against an unfolding genocide. Palestine, once a marginal issue, has become a mainstream one that lies at the heart of western politics and discourse. And yet, as long as governments with leverage over Israel refused to act, none of that saved a single life.

There is still something in this moment that could be expanded into something meaningful. Politics tends towards inertia – the observance of alliances and the status quo. To upend that requires real crisis, yet Israel has managed to escalate its campaign in Gaza to a level that has scaled even that high bar. Standing by as a population starves, watching lives ebb away in plain sight, seeing the ribs and hollowed eye sockets of lethargic children, governments are tarred with the stain of complicity. To deprive people of food, to have such power over them, is not a military campaign of strategic goals involving regrettable collateral damage – it is the creation of a ghetto of mass punishment. A defining chapter of history is being written. The sponsors of this act are clearly identifiable, emphatically supportive, and yet now seem thrown off by the position they find themselves in. Duration also plays a role. It’s all gone on for too long and it has become clear that it is impossible to force through a habituation to mass murder. But it might also be this particular phase of Israel’s campaign, which is luridly more savage and naked in its intentions than it’s ever been.

If this new attitude taken by western leaders is designed to fend off a reckoning, then it’s too little, too late: the record has already been taken. If it is to deter Israel from following through on its plans of scorching the conditions for life, forcing people to leave, and starving and killing those who remain, then they are facing down a juggernaut using little more than press releases. The gulf between Israel’s actions and the world’s reaction is still too wide to be proportional. The Israeli prime minister, Benjamin Netanyahu, has already insulted France, the UK and Canada, accusing their governments of siding with Hamas just for finally stating the obvious: that Israel should stop killing and starving people. In what world does a member of government declare that it intends to wipe out what remains of an area and aims, “with God’s help”, to remove its inhabitants, only for the response be nothing more than vague threats of “concrete action”? What deterrence is required to stop a doctor going to work and then returning to the charred remains of nine of her 10 children, wiped out in a single blow?

It will take far more than the reviewing and suspension of future trade talks between Israel and the UK. Those mechanisms of censure that signal displeasure and motivate outlaws to come back into the fold have been shattered by an Israel that has made a virtue out of being outside it: the kind of action required would necessitate the overturning of deeply held fears and assumptions. First, the now risible belief that Israel is a stabilising ally in a hostile region, that it is a country that shares civilised western values and so should be supported. Then, the fear of a rift with Israel that will violate security arrangements and historical synergies – after all, Israel has already brought that about. It has upended regional and global political and moral settlements, and its allies have still not caught up. Once these truths have been accepted, the toolkit, so easily deployed to sanction other countries, is there to be mobilised. The US remains the party with the most influence, but it is not the only player. The EU constitutes about a third of Israel’s total global trade: an embargo should be sought. Sanctions should be imposed, not just on settlers but on the politicians in government who have enabled them. The international criminal court’s rulings on Israeli leadership should be observed. A blockade should be enforced, one that establishes in practice the pariah status that the Israeli government has long ago earned in principle.

And even then, all this would only be a start, and a colossally, tragically late one at that. One can break down why none of these things have yet happened: the hopes that keeping Israel on side preserves some modicum of leverage; concerns that strong measures will embolden Iran; loyalty to the notion of historic debt; fears of the uncertain world that a break with Israel would usher in. But that world is already here, and cowardice has only accelerated its arrival, rather than prevented its emergence.

Palestinians, from Gaza to the West Bank, are paying the highest price for inaction, but an acute wound has been inflicted on the rest of the world. If nothing happens, its moral and political morbidity will encompass all.