WHEN Russia dispatched its warplanes to prop up the dictatorship of Bashar al-Assad, Barack Obama warned Moscow that its Syrian adventure was doomed to fail. Russia will get “stuck in a quagmire and it won’t work”, Mr Obama confidently predicted in October 2015. Russia’s air force has since proven the American president profoundly wrong.

On November 28th pro-government forces backed by Russian bombers finally punched through rebel lines in the east of Aleppo. The breakthrough came two weeks after pro-regime forces launched an operation to recapture the rebels’ last big urban stronghold. With the regime now in control of at least a third of the city’s east, the fall of Aleppo looks almost certain.

For months the regime has sought to strangle the city’s rebel-held east into submission. A siege has slowly sapped the strength and morale of its defenders. As the blockade tightened, Russian and Syrian warplanes relentlessly bombed civilian infrastructure, destroying hospitals, schools and bakeries in a bid to drain support for opposition fighters by making life unbearable for the east’s 250,000 or so remaining civilians. These tactics, which have forced rebels to surrender in other parts of the country, have crippled eastern Aleppo. Food rations have almost run out and medical supplies are low. With the city’s hospitals destroyed, doctors now treat patients in the basements of homes.

Spearheaded by thousands of Hizbullah and Iraqi militiamen, this week’s swift advance of pro-regime forces has driven thousands of terrified civilians from their homes. They face a grim choice: stay in the east and face the bombs, or flee into areas controlled by a government that has arrested and tortured its opponents since the start of the war in 2011.