"The duty to prevent and halt genocide and mass atrocities lies first and foremost with the State, but the international community has a role that cannot be blocked by the invocation of sovereignty."
The United Nations said that in 2005 about its "responsibility to protect." It's the concept that "if a State is manifestly failing to protect its populations, the international community must be prepared to take collective action to protect populations."
And here is what UN officials said this week when describing what is happening in Syria: "A complete meltdown of humanity in Aleppo."
Apocalyptic images of a once-vibrant historic city now reduced to an emaciated shadow of its former self have played out for the world to see.
Sustained months of Russian air strikes and Syrian regime barrel bombs appear to have done their work.
Bombs falling from the sky onto homes and streets and schools below shifted facts on the ground and left moms and dads and children seeking shelter and safety that still has not yet showed up.
The world has watched in real time as the hell of the Syrian civil war has caught families in its grip and refused to let go.
Five and a half years of war
Hundreds of thousands dead. Four million-plus forced to become refugees.
Double that number displaced. Millions of children out of school.
And now, in Aleppo, Syrian forces, backed by Iranian-supported militias and Russian strikes, appear poised to recapture the city which had been split in two for more than three years.
The city that was the country's most populous before the devastation of the civil war.
Siege, starvation and the reported execution of civilians in plain sight.
The UN says it has "reliable evidence that in four areas 82 civilians were killed, adding that many more may have died."
Rubble everywhere and safety nowhere
And how has the international community responded? They have talked, spread blame and talked some more. The United Nations on Tuesday found itself home to yet another diplomatic standoff in the face of Aleppo's downfall, this time with sharp words for Syria, Russia and Iran from the US Ambassador to the UN.
"Your forces and your proxies are carrying out these crimes. Your barrel bombs and mortars and air strikes have allowed the militia in Aleppo to encircle tens of thousands of civilians in your ever-tightening noose," US Ambassador to the UN Samantha Power said.
"Three member states of the UN, contributing to a noose around civilians. It should shame you."
But shame is not the hallmark of the Syrian civil war. Barbarism is.
Pinned-down civilians facing unspeakable crimes are sending goodbye messages as they wait for death. As they face further shelling, diplomats discuss a ceasefire that may or not may not take hold.
'Never again'?
"The words 'never again' ring hollow today with reports that Aleppo is falling to Assad regime forces," Senators John McCain and Lindsey Graham said in a statement.
"For four long years, Aleppo has been at the center of the Assad regime's war on the Syrian people ... Together with its Russian and Iranian allies, the Assad regime has relentlessly targeted women and children, doctors and rescue workers, hospitals and bakeries, aid warehouses and humanitarian convoys."
That "responsibility to protect" has been shown to be three words that mean precious little.
Rest in peace, R2P. It ended before it even really began.
Syria is the war that has run out of adjectives. No words fully capture the horrors of the starvation on the ground and the carnage wrought by bunker-busters and barrel bombs from the sky.
Parents' lives and children's burials are left to do that.
Gayle Tzemach Lemmon is a senior fellow at the Council on Foreign Relations and author of the New York Times best-seller, Ashley's War: The Untold Story of a Team of Women Soldiers on the Special Ops Battlefield. The opinions expressed in this commentary are hers.