Obama did nothing.
In Aleppo no one is talking about red lines.
As the forces of Syrian President Bashar al-Assad advance on the last rebel-held section of Aleppo, aid groups and activists describe horrific scenes of death and bloodshed.
U.N. agencies say they have received reports of indiscriminate killings and children under fire, and aid groups are desperately calling for parties to observe "the basic rules of warfare — and of humanity," as the International Committee of the Red Cross put it.
Negotiations to arrange for civilian evacuation have failed so far, although Turkey and Russia are reportedly still discussing the possibility. Meanwhile, those who remain in the small patch of rebel-controlled Aleppo have been saying goodbye to loved ones on social media.
Aleppo — once Syria's largest city, and a major commercial hub — has been divided between government and rebel forces for four years. In the last month, Assad and his allies have waged an offensive to retake the entire devastated city.