On Jan. 26, 1991, the military forces of the United Somali Congress entered Mogadishu, Somalia's capital, and occupied the palace of President Siad Barre, driving him into exile in neighboring Kenya and ending his 22-year reign as leader of Somalia.

Barre's removal, led by Gen. Mohamed Farrah Aidid and Ali Mahdi Mohamed, could have been an opportunity for political evolution in Somalia. But instead of collaborating, the coup leaders succumbed to infighting.

Mahdi's faction in the USC appointed him president just two days after the overthrow of Barre, but Aidid refused to recognize Mahdi's presidency.

"[Aidid and Mahdi] couldn't agree on who appointed themselves president," said Abdi Samatar, a Somali national and professor of geography at the University of Minnesota. "So clashes between the groups appeared."

This vacuum of power ushered in a new era in Somalia, one ruled by multiple warlords and defined by constant violence, chaos and instability.

"This was the ascent of the warlord era in Somalia," said John Prendergast, senior adviser at the International Crisis Group. "The factions at the time were like alphabet soup, splitting and atomizing along sub-clan lines on a daily basis."

The northern part of the country declared its independence as Somaliland, leaving the warlords to operate freely throughout the southern region.

"It was a dangerous and uncertain period for residents of southern Somalia," said Prendergast, who served as a policy adviser during the Clinton administration. "The country was broken into mini fiefdoms."

As the warlords vied for power, territory and supporters, the situation disintegrated into a civil war that, by the end of 1991, had ravaged the country.

In the fighting between the two most powerful factions, helmed by Aidid and Mahdi, food was used as a weapon. As a result, a widespread famine devastated the region.

"Roads were held by gangs, supplies had been cut off to farmers, and food shipments were not getting through," Samatar said. "[The famine] was not natural, but created by Aidid."

Almost 1.5 million people were affected by the famine, according to U.N. background reports. In 1992, U.S. and U.N. troops were sent to Somalia to ensure the safe delivery of humanitarian aid and to help mitigate violence levels.

"The troops opened the roads for food shipments and the famine virtually ended," said Samatar. "The U.S. and U.N. had no clue as to what created the problem."

Some warlords benefited from the international presence in Somalia, receiving money and housing contracts, while others, like Aidid, rejected the U.N. and U.S. involvement.

The second U.N. operation in Somalia, which started in late 1992, brought together warlords from around the country in an attempt to unify the different factions under one government.

Initially, the faction leaders agreed upon a country divided into 18 autonomous regions and commenced disarmament talks. But the process was disrupted in June 1993, when 24 Pakistani U.N. peacekeepers were killed in Mogadishu by Aidid's men.

Violence immediately escalated in Mogadishu between peacekeeping forces and Somalis. After a year of rising tensions -- and the deaths of 18 American soldiers in a failed attempt to capture or kill Aidid -- the United States decided to withdraw.

"Clinton said, 'let's pull soldiers out,' and in doing so, left a vacuum," said Samatar.

By the mid 1990s, dozens of warlords held power throughout Mogadishu and the rest of the south.

Throughout the rest of the decade, tenuous alliances between warlord-led factions brought attempts at reconciliation, but ultimately, an agreement to develop a central government was never reached.

"The efforts throughout the 1990s were plentiful to reconstitute an authority and every one failed miserably," said the Crisis Group's Prendergast.

In the early 2000s, progress toward a centralized authority was made as some warlords convened in a series of reconciliation talks that led to the development of the Transitional National Government. However, influential warlords, like Mohamed Aidid's son, Hussein, refused to recognize any attempt at a central authority.

"[The TNG] moved to Mogadishu and Aidid and all these other people saw this as a pro-Islamist government," said Gregory Pirio, author of "The African Jihad: Bin Laden's Quest for the Horn of Africa."

Aidid and sympathetic warlords founded an opposing group, the Somalia Reconciliation and Restoration Council, in 2001, but in 2003 reached a compromise and decided to become involved with the TNG.

The TNG was short-lived, but the warlords remained involved in the efforts to form the current Transitional Federation Government in 2004 in Kenya.

"They had actual, physical fights in Nairobi [in 2004] working out a solution, but they did do something," said Pirio.

With the assimilation of warlords into the government and the spread of the Islamic Courts movement, the warlords' anarchical reign was effectively diminished for the first time in 15 years.

In the fall of 2005, violence between warlords reignited. They started to fight each other again for territory throughout Mogadishu, replete with weapons and money that was surreptitiously being distributed to them by the U.S. government.

The Central Intelligence Agency was concerned that, with the unstable Transitional Federal Government operating from outside the capital, the Islamic Courts in Mogadishu were hiding al-Qaida operatives.

"The Americans were telling the warlords, form a coalition of anti-terrorism and we'll help you," said Prendergast. "The warlords were wandering around town with big wads of cash and trying to wipe out the courts."

But by the spring of 2006, the operation had been uncovered as the Islamic Courts fought back against the warlords, effectively defeating them and driving them out of Mogadishu. The CIA plan had backfired and the warlords again maintained little influence in the southern part of Somalia.

The balance of power shifted once more in December 2006, as the warlords and the transitional government, who received support from invading Ethiopian troops, helped drive the Islamic Courts virtually out of the country.

"Warlords came back with the Ethiopian tanks, but you can't keep moving back and forth," said Samatar. "It's similar to what happened in spring of 2006, but this time the Ethiopian forces seems to be providing the warlords with the protection and most of them are operating freely."

If a solution to the incessant power swings will ever be found it lies, according to Samatar, with successful disarmament of the warlords. But he remains skeptical.

"Whether the TFG will be able to disarm the warlords, we don't know," he said. "But if the Ethiopians act as a neutral force that protects the TFG and the population, that will be more positive."

-- By Jon Brand, Online NewsHour