Sarin, one of the world's most lethal chemical weapons, has long been stockpiled but is rarely used by states or terrorists. Allegations of attacks on civilians in Syria, if substantiated, would represent a departure from longstanding international practice, this Backgrounder explains.
Global monitors say Iran's human rights situation is poor and unlikely to improve amid a climate of political uncertainty and growing external pressures. But activists urge continued international scrutiny of Iran's violations.
The future of the Muslim Brotherhood, Egypt's largest opposition movement and a standard bearer for Islamist groups around the world, remains uncertain following Mohammed Morsi's fall, explains this Backgrounder.
The People's Mujahedin of Iran, or MEK, is a militant Iranian opposition group and a recognized terrorist organization, according to the U.S. State Department. This Backgrounder examines the group's history and the politics surrounding its relocation from Iraq.
Targeted killings have become a central component of U.S. counterterrorism operations around the globe. Despite pointed criticism over transparency and accountability issues, analysts say the controversial practice seems likely to expand in the future.
Founded as a loose confederation of states in 1945, the Arab League has struggled to overcome dysfunction and disunity among its members. The Arab revolts of 2011 offer the League a new opportunity to pursue necessary reforms, increase legitimacy, and prove its relevance.
With oil supplies tight, regions most vulnerable to oil supply disruptions present a significant economic concern, particularly threats to the Strait of Hormuz and unrest in Nigeria, explains this Backgrounder.
Al-Qaeda in the Arabian Peninsula has emerged as the most dangerous al-Qaeda affiliate, strengthening amid political unrest in Yemen. This Backgrounder examines the group and U.S. counterterrorism operations.