So the United Nations believes that Israel committed war crimes in Gaza, and Israel is aggrieved. It has a point — but that does not mean the allegations are wrong.

The investigation into crimes committed by both sides during Operation Castlead was ordered by the UN Human Rights Council, an international body so utterly lacking in credibility or balance that this summer it passed a resolution praising Sri Lanka for defeating terrorism rather than ordering it to investigate alleged war crimes that caused an estimated 20,000 civilian deaths.

Both orders were political decisions. The Human Rights Council is a body made up of representatives from a range of countries sitting on a panel in Geneva, none with veto power, unlike the powerful Security Council at the UN in New York.

Thus the United States could not “protect” Israel as it habitually does on the Security Council, nor prevent the well-established anti-Israel prejudices of the Geneva body from prioritising a wholly legitimate investigation into alleged war crimes in Gaza.

Sri Lanka fared better. It was able to marshall all sorts of dubious and self-interested allies to its side, not only to see off an investigation, external or internal, but to heap praise on itself for its achievement in crushing the Tamil Tigers.

So Sri Lanka avoided investigation. Israel did not. But having been investigated, and by a panel led by one of the most respected international jurists in the world, Richard Goldstone, Israel turned round and called it a “kangaroo court.”

Justice Goldstone was the lead war crimes prosecutor for former Yugoslavia and Rwanda. He know a thing or two about war crimes. If he believes that they were committed in Gaza, I suspect he is on to something.

In January this year, The Times uncovered the first judicially compelling evidence that Israel was using white phosphorus in civilian areas, resulting in horrific burns and death. That was only one of 36 cases or charges that Justice Goldstone examined for his report.

The Human Rights Council, for all its uneven focus on Israel at the expense of other conflicts, often far richer in war crimes, was right to order an investigation. It was absolutely, utterly and wholly wrong to gloss over Sri Lanka’s alleged crimes with praise.

The problem is in the tangled politics of referral. If that system is politicised or seen to be, then international justice stands no chance. War crimes cases arrive at the International Criminal Court only after it is determined that the responsible country is unwilling or unable to prosecute, and then by one of three methods: self-referral in the case of a willing non-signatory, compulsion by any signatory country, or a vote by the UN Security Council in the case of a country that is neither willing nor signed up.

Luis Moreno Ocampo, the chief prosecutor of the ICC finds himself constantly criticised for the countries he “picks” on for prosecution – all, so far, anarchic African states. But while he can investigate any case brought to him, it is not up to him who he prosecutes, and he finds himself continually thwarted by competing political interests.

The setting up of a system of international justice will always be a rocky one. And it will always seem, in the initial phases, that certain countries are being picked on. The answer is not to let them get away with it.

Hillary Clinton has already said she would like to see the US sign up to the ICC during this administration. That would go a long way to helping embed international justice in the global psyche as the fair way to handle the most heinous of crimes.

Israel may have ended up in a dock that others like Sri Lanka have avoided but now it is there, it must face the music.

Washington must not block a Security Council vote forcing Israel to have its own, truly independent inquiry. And the consequences of not doing so must be clear. Only when every country on the planet shares those same consequences, and knows it, will the fight against war crimes really have begun.

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