The Washington Post reports: A fast-moving cataclysm underway in and around Aleppo has brought together all the major actors in Syria’s civil war for what may be the most crucial battle of the five-year conflict, and it is testing whether U.S.-Russian cooperation to end it is a pipe dream.

North of the city — in which the government holds the western side and U.S.-backed moderate opposition forces have occupied the east since 2012 — the opposition has lost control of its only lifeline for resupply under relentless pummeling by Russian and Syrian aircraft and artillery.

The road to Turkey also provided the only path for humanitarian aid or an escape route for at least a quarter-million civilians trapped inside Aleppo, who the United Nations said this week have been left without food, medical supplies or running water.

So dire is their situation that talks initiated by the Obama administration with Russia this summer about coordinating their Syria counterterrorism efforts have been put on the back burner, superseded by urgent negotiations with Moscow over reopening the road to Turkey, according to U.S. officials. [Continue reading…]

In the video below, Charles Lister discusses the siege of Aleppo and the dynamics within Syrian opposition groups: