Throughout his thirty-year reign, Egyptian president Hosni Mubarak never so much as hinted at a possible successor. Until this weekend, the 82 year-old former air force commander had never even appointed a vice president. But as protests continue in the streets of Cairo and other major cities in northern Egypt, the question of Mubarak’s succession has become relevant.

Mubarak served as Egypt’s vice president between 1975 and October 1981 when Anwar El Sadat was assassinated by Islamic radicals, angered by the late president’s willingness to make peace with Israel.

Throughout Mubarak’s years in office, Egypt’s largest opposition party, the Muslim Brotherhood, has been banned out of fear of religious extremism.

As demonstrators took to the streets last week to demand Mubarak’s resignation, Israeli and Western leaders have called for an “orderly transition” in Egypt, worrying that a power vacuum could easily be filled by fanatics.

Both Mubarak and his newly appointed Vice President Omar Suleiman have recently warned that “chaos” might ensue if the president were to immediately resign. In an interview with ABC’s Christiane Amanpour on Thursday, the embattled president specifically reiterated his longtime concern about Islamists taking over in the country.

In response to the civil unrest, Mubarak announced on Tuesday that he would not stand for reelection in September. He said he would “die on the soil of Egypt” however and that his first responsibility now was to “restore the security of the homeland [and] to achieve a peaceful transition of power in an environment that will protect Egypt and Egyptians.”

One of the most decisive figures in the upper echelons of Egypt’s civil administration is now Omar Suleiman, formerly the chief of the intelligence services and a trusted ally of Mubarak’s.

Suleiman has a military background and as head of the country’s secretive but extensive intelligence apparatus, he successfully defeated an Islamist insurgency in the 1990s. He would be the establishment’s (if not the West’s) preferred candidate but protesters who are fed up with the Mubarak regime are unlikely to think of the 74 year-old as the right man to user in a new era of democracy in Egypt. Suleiman himself told ABC News that he isn’t thinking about running for president.

It was long presumed that Mubarak was grooming the youngest of his two sons, Gamal, to succeed him. Suleiman ruled out that scenario in an interview with Egyptian state television on Thursday.

Other candidates include General Sami Hafez Enan, chief of staff of the Egyptian armed forces. Reportedly, the United States have been pressing Enan into coordinating an interim government in the event Mubarak falls. As the military plays a key role in Egyptian politics, so does Enan.

The Egyptian armed forces are the largest in the region and also among the most powerful, after Israel’s. The military enjoys considerable power independent of civil authority and considerable prestige among all segments of the Egyptian population.

Amr Mohammed Moussa, formerly Egypt’s foreign minister and Secretary General of the Arab League for close to ten years now, is another potential contender.

When Mubarak nominated Moussa for his current position, it was rumored that the president intended to remove the popular minister from the public spotlight in Egypt. He has been urged to run for the highest office before but has so far avoided questions about his current presidential ambitions.

When Moussa returned to Egypt during the unrest, he met with the former head of the International Atomic Energy Agency (IAEA), Mohamed ElBaradei, who has spoken on behalf of the opposition in recent days.

Although well known among intellectuals and outside of Egypt, ElBaradei’s public appeal may be hampered by his lack of recognition among ordinary Egyptians. He has long worked abroad and served as director general of the IAEA for ten years.

ElBaradei returned home after protests broke out in Egypt to play a political role in the coming period of transition. Reports of his relation with the Muslim Brotherhood have been contradictory. Some media outlets reported that he had been mandated by the organization to negotiate on their behalf but others denied this.

The regime has so far remained defiant in the face of civil unrest, urging restraint on the part of demonstrators and stating, in the words of Vice President Suleiman, that their demands are being met.

On Friday, thousands took to the streets of Alexandria and Cairo again to demand Mubarak’s immediate ouster. Whether he manages to remain in office until after the summer seems doubtful at this point. The White House is reportedly already in talks with Suleiman and the military to enact constitutional reforms and begin a period of transition.