The provisional measures issued by the international court of justice ordering an immediate halt to Israel’s military operation in the southern Gaza city of Rafah represent the starkest warning yet to Israel that its offensive risks creating conditions that could be framed as potentially genocidal.

The ruling, agreed by a majority of 13-2 judges, almost exclusively cited UN agencies and senior officials – including the UN’s secretary general – to paint a picture of the disastrous situation facing Palestinians in Gaza, half of whom are children.

Israeli officials had vowed to defy any new order, but the ICJ measures – the country’s third major setback on the global stage within a week – underline the stark and deepening risk for Israel and its leaders, faced with mounting international fury over their behaviour.

After the application to the international criminal court for arrest warrants against Benjamin Netanyahu and his defence minister, Yoav Gallant, as well as Hamas leaders, and Spain, Norway and Ireland’s announcement that they would unilaterally recognise a Palestine state, Friday’s court order shows Israel’s growing isolation.

While the US has said it would push back against the ICC warrants, the ICJ ruling undermines efforts to present the court cases against Israel as somehow being in bad faith, instead affirming that the world’s two top international courts agree that allegations Israel is committing the most serious of war crimes are indeed plausible.

Most damning is the detail of the court’s ruling. A situation the court had already ruled as catastrophic had become even worse since it first ordered provisional measures – and was in danger of intensifying, it said. Israel’s assurances that it could adequately evacuate and protect from violence hundreds of thousands of civilian were not “sufficient” and had not dispelled concern over the operation.

Appearing to echo a key phrase from the genocide convention, the court’s president, Nawaf Salam, ordered: “The state of Israel shall […] immediately halt its military offensive, and any other action in the Rafah governorate, which may inflict on the Palestinian group in Gaza conditions of life that could bring about its physical destruction in whole or in part.”

In recent jurisprudence on international humanitarian law, the phrase “in whole or in part” has come to be framed as the so-called “quantitative criterion” – the question of when the scale of potential loss of life, and physical means of life, reaches a threshold of genocide, in conjunction with the issue of intention.

The court appeared to address that question in other parts of its ruling, referring to the large numbers of deaths and injuries as well as the massive destruction of homes, forced displacements and destruction of civilian infrastructure.

While Israel’s leaders dismiss claims of genocide and have insisted that their campaign against Hamas is justified under the right of self-defence, the ruling will be seen as another important data point in the accumulation of evidence against the way Israel is conducting the war.

Israel’s diplomatic isolation – recognised as a reality by senior White House officials – is likely to have a widening impact, as it has also exposed the increasingly weak and contradictory leadership of the Biden administration on the issue as countries have broken ranks with the US-led post-Oslo consensus that has reigned for decades.

The ruling also poses practical problems for Washington’s support for Israel in the courts. With both of the top international courts in lockstep, the White House is in danger of signalling that its long-term insistence on the primacy of international law is hollow when it comes to protecting its allies.

Even more complicated for the Biden administration is that the ruling underlines what has become an international consensus, shared by the US: that an immediate ceasefire, at the very least, is required to protect civilian life.

The unanswered question is what it will mean for Netanyahu and for Israel. Confronted with the threat of an arrest warrant for war crimes from the ICC, with an unequivocal order from the ICJ, warnings from almost every major UN agency, and once friendly governments openly abandoning their former policies to unilaterally support Palestinian statehood, the exposure of Israel and its leaders can only get worse.