—REFUGEES: U.N. humanitarian chief Valerie Amos says the growing number of Syrians affected by the civil war in Syria is now 4 million and rising. They include an estimated 2 million displaced within Syria and nearly 925,000 who have fled the country. Most of the refugees have gone to neighboring Turkey, Jordan and Lebanon, and the influx is outstripping those countries' and the international community's ability to help.
—INTERNATIONAL ALLIANCES: President Bashar Assad can count on his traditional Shiite allies, Iran and Lebanon's Hezbollah. The regime also enjoys crucial political cover from Russia and China, which have used their vetoes in the U.N. Security Council to prevent U.N. sanctions on Syria.
The rebels have built an array of regional support that includes the wealthy Gulf states—led by regional Sunni power Saudi Arabia—and neighboring Turkey, which offers key supply routes.
—THE FIGHT ON THE GROUND: The regime has lost significant swaths of territory to the rebels, particularly in the northeast near the border with Turkey. But while the rebels control most of the countryside, the Syrian military remains in control of most of the cities. Currently, the two key fronts in the war are in Aleppo, the country's largest city and a former commercial hub, and in Damascus, the capital.
Aleppo has been carved into rebel- and government-controlled zones, and neither side has been able to overwhelm the other in a contest that has descended into a brutal slog for each city block.
In Damascus, the regime is relying on its best equipped and most loyal troops, and has managed to keep a tight grip on the center of the city. Some of the capital's suburbs, however, have been rebel strongholds since the early days of the uprising, and opposition fighters are using the towns and villages on Damascus' doorstep to slowly try to push their way into the heart of the city.