The crisis in Aleppo, explained in 4 minutes

The Syrian city of Aleppo has come up again and again in the US presidential campaign — because at least two candidates have no idea what to say about it. But understanding what’s happening in Aleppo right now is critical to understanding the situation in Syria. If you watch the above video and read the below text, you can consider yourself better informed than Gary Johnson and Donald Trump.

Aleppo is a city located in Northwest Syria near the Turkish border. It’s the capital of the eponymous Aleppo province and was the country’s most populated city before the war. Today it’s perhaps the most significant battlefield in Syria’s defining conflict: fighting between Bashar al-Assad and various anti-government rebel factions. (ISIS is not a major player in Aleppo City, though it has a presence in Aleppo province.)

Since Syria’s 2011 Arab Spring protests descended into a civil war, Aleppo has been a major base for a number of different rebel factions opposed to the Assad regime. In September 2015, Assad’s forces began a concerted effort to retake the city. Prior to the Aleppo offensive, Assad had been losing. In response, his international patrons — Russia and Iran — began increasing their support in the fall of 2015. Their deployments allowed Assad’s forces to make their major push toward the city, the latest in a fundamental seesaw dynamic in momentum that has characterized the Syrian civil war for years.

The worst-case scenario has always been a full-on siege of the city’s rebel-controlled Eastern half, blocking even humanitarian assistance from getting in. This sort of siege is illegal under international law, but Assad has been doing it for years. That’s because it works: Rebels who don’t have food quickly lose the will to fight, and civilians in besieged areas will start cooperating with the government just to make it stop.

In July, these fears were realized. The Assad regime, with significant support from Iran, imposed a blockade on rebel areas, cutting off supplies to more than 200,000 people.

At the end of July, the fractious rebel groups struck back, launching a rare coordinated offensive that caught the Assad regime off guard and temporarily broke the siege. But in September, the siege was reimposed. It remains ongoing today, and the humanitarian situation for Aleppo’s trapped civilians remains dire. And the US has no good policy option to break it.

So Aleppo isn’t just one site of tragedy among many in Syria. It’s a humanitarian crisis and one of the most important battlefronts in the country — the kind of thing that someone who wants to be president of the United States should at least have passing familiarity with.