Crisis in Syria: how the most violent uprising of the Arab Spring could change the balance of power in the Middle East.

• Author: Smith, Patricia
• Position: Cover story

The toll has been staggering. In the year since protests sparked by the Arab Spring began in Syria, more than 8,500 Syrians have been killed and thousands more are missing. Entire neighborhoods have been destroyed by government shelling.

As the dead pile up and diplomacy fails to stem the violence, the upheaval in Syria threatens to spill beyond the country's borders and alter the power balance in a volatile region of critical interest to the United States.

So far, the Arab Spring revolutions have overthrown authoritarian regimes in Tunisia, Egypt, Libya, and Yemen. But a regime change in Syria could have much wider ripple effects.

"In Syria, if the regime is toppled, we have a totally new landscape," says Olivier Roy, a Middle East historian.

That possibility is prompting both hope and fear: hope that the days are numbered for a regime that has long been a thorn in Washington's side, and fear about what will take its place and whether it will lead to further instability.

Syria is a dictatorship ruled by President Bashar al-Assad, who inherited power from his equally authoritarian father in 1999. The Assad family, the ruling elite, and the military leadership are all Alawites, a minority Shiite sect that makes up about 12 percent of Syria's population (see Who's Who in Syria). About 75 percent of Syrians are Sunni Muslims, and they make up the backbone of the opposition.

Firing on Civilians

The upheaval in Syria began in March 2011, when residents of the small city of Dara'a took to the streets to protest the torture of students who had put up antigovernment graffiti. The government responded with force, and demonstrations quickly spread across the country. Assad has since overseen a series of crackdowns, sending tanks into cities as security forces opened fire on demonstrators.

In February, government troops surrounded part of the city of Horns, turning heavy weaponry on apartment buildings and killing many civilians. The army wouldn't allow food or medical supplies in or the wounded to get out.

"Please tell the world they must help us," 20-year-old Abdel Majid told The Sunday Times of London.

The United Nations and the Arab League have condemned the crackdown. In February, a U.N. report said the Syrian government's actions amounted to crimes against humanity.

"It is time to stop the killing of Syrian citizens by their own government," said President Barack Obama, who has called for Assad to relinquish power.

Despite the international...