President Ali Abdullah Saleh and his family
He has maintained his hold on power through an extensive patronage network, which includes members of his family and tribal leaders. He's been a master at playing various factions against each other and preventing the emergence of a strong and unified opposition. Saleh’s family is part of the Sanhan tribe, which belongs to the large and powerful Hashid tribal confederation.
Saleh’s oldest son, Ahmad Ali Saleh, is head of Yemen’s elite Republican Guard and the country’s special forces, which have stood by Saleh as other military units defect. Prior to the current unrest, he was being groomed to succeed Saleh as president.
Saleh also installed several of his nephews in government positions, overseeing the country’s national security, central security, counterterrorism forces, and presidential guard. Saleh’s half-brother, Mohammed Saleh Abdullah al-Ahmar, leads the country’s air force. Dozens more members of the Saleh family have vast land and economic holdings – everything from oil and tobacco companies to Yemenia Airlines – as well as government and security positions.
Even if Saleh did opt to step down, it wouldn’t be the end of the Saleh family’s power.
The Ahmar family
Fierce clashes in Sanaa have pitted Saleh’s forces against tribal fighters commanded by the Ahmar family, one of the most powerful in Yemen. Sadiq al-Ahmar, the eldest of 10 brothers, is also the titular head of the powerful Hashid tribal confederation – one of Yemen’s two main tribal confederations. The confederation, which includes Saleh’s Sanhan tribe, has become one of the biggest challenges to the president as tribal fighters clash with Saleh loyalists in the capital.
Sadiq is elderly and unlikely to take on more than a figurehead role, but his brother Hamid is a leading politician in the Islah party, which was founded by the Ahmar family and is one of the most powerful opposition parties in the country. He was a vocal opponent of the president well before the current uprising and has fashioned himself as a potential successor.
The father of the Ahmar brothers, Abdullah bin Hussein al-Ahmar, was a major figure in Yemen. As head of the Hashid confederation, of Islah, and speaker of the lower house of parliament from 1993 to his death in 2007, he was said by some to be Yemen’s second-most powerful man after Saleh.
Two of his other sons are also political figures. Himyar al-Ahmar was deputy speaker of parliament until he resigned in March, and his brother Hussein was a member of the ruling party, the General People’s Congress, but resigned in February.
Gen. Ali Mohsen al-Ahmar
Gen. Ali Mohsen al-Ahmar was the most powerful figure in Yemen’s military until he broke ranks with Saleh in March to support the protesters, vowing to protect them. He was one of the country’s top military commanders, a big supporter of Saleh (a WikiLeaks cable described him as Saleh’s “iron fist”), and was a member of Saleh’s Sanhan tribe.
Gen. Ahmar is not a member of the powerful Ahmar family, but he is said to be a half-brother of Saleh. Any familial loyalty that existed may have been broken last year. In Yemen, it's widely believed that Saleh tried to trick the Saudis into killing Ahmar.
In a US diplomatic cable released by Wikileaks, US Ambassador to Saudi Arabia James Smith recounts a conversation with Khaled bin Sultan, Saudi Arabia's assistant minister of defense and aviation, in early 2010.
The Saudis at the time were bombing Houthi rebels in support of Saleh, often with intelligence provided by his government. One mission was aborted by the Saudi pilots involved at the last minute because it didn't feel right. Prince Khaled told Mr. Smith that a Saudi investigation found that the coordinates provided were in fact Ahmar's headquarters.
The political opposition
The country’s main opposition parties are represented by the umbrella coalition group known as the Joint Meeting Parties (JMP). In the early days of Yemen’s uprising, the JMP attempted to negotiate a deal with Saleh to step down, but it failed.
The country’s strongest opposition party is the Islah party, which began as part of the ruling coalition but broke off in 1997 and joined the opposition. It was founded by the powerful Ahmar family and holds about 20 percent of the country’s parliamentary seats. The party is made up of both Islamists and tribal leaders, who are often at odds with each other because of their divergent interests.
Prior to the unification of Yemen in 1990, southern Yemen was an independent socialist state. It tried to secede in 1994, leading to a bloody civil war that ended in triumph for Saleh and his vision of unification. The separatists are still quite popular in the south, mostly due to grievances about unequal distribution of resources by the north.
The southern movement supports the antigovernment protesters, but its demands for economic equality and greater political representation go far beyond Saleh’s resignation.
The Houthi rebels’ have announced their support for the anti-Saleh protesters, although it’s unclear what their end goals are. The rebel group, based in Yemen’s northwest, has been clashing with the Sunni-led central government and army since 2004. They consider their branch of Shiite Islam to be threatened by Saudi Arabia, whose Wahhabi strain of Islam is at odds with theirs and whose leaders have helped Saleh put down the rebellion along their shared borders. Houthis are also angry at the lack of economic assistance from Sanaa to their region of the country.
The Yemeni government has accused the Houthis of being an Iranian terrorist group.
Islamist militants (AQAP)
Yemen is home to various militant groups, most notably Al Qaeda in the Arabian Peninsula (AQAP). The group was formed in January 2009 when existing operations in Saudi Arabia and Yemen were combined; the merger was acknowledged by Osama bin Laden's deputy Ayman al-Zawahiri.
AQAP has made clear its intent to attack Western targets. Notable efforts were the 2009 Christmas Day bomb plot and 2010 cargo plane plot – both of which were foiled.
Many have accused Saleh of playing up the AQAP threat to boost aid from the US, which has increased funding significantly over the past few years. Saleh was given $70 million in US military aid last year and was scheduled to receive $150 million this fiscal year.