After it was announced yesterday that Yemeni President Saleh had left the country for Saudi Arabia amid massive protests and escalating violence, with the nation teetering on the edge of civil war, thousands of demonstrators celebrated in the street on Sunday. Many believed Saleh's departure was akin to the resignation of Hosni Mubarak, the latest ouster of a despot after popular uprising. "This is it, the regime has fallen!" they chanted in the streets, according to Al-Jazeera. But has it? Saleh's departure remains somewhat shrouded in mystery. Yemeni officials have been scarce with details, and what details they have provided have been conflicting. Each plausible explanation for Saleh's departure in turn has several severe implications for Yemen; there is no consensus that his leaving will reduce the violence in the region. Here are the prevailing theories as to why Saleh has left for Saudi Arabia seeking medical treatment.

Theory #1: It's just a scratch, and Saleh will return to Yemen

Supporting evidence. This remains the official statement by Yemeni officials. In the initial report after the attack that injured Saleh, Yemen's deputy information minister said Saleh had "scratches on his face." And despite the trip to Saudi Arabia, Tareq Shami, a spokesman for the ruling party, described the treatment Saleh was receiving in Saudi Arabia as "simple checkups," according to the Wall Street Journal. "Saleh is not sick and he will be back to Yemen soon," he added, specifying that he would be "back in Sanaa within days," according to Al-Jazeera.

Counter evidence. "If he was just suffering minor injuries then I would assume it would have made sense for him to be treated in Yemen," said an Al-Jazeera correspondent. "The fact that he was flown to Saudi Arabia says a lot about the end of the Saleh era."

What this means. If Saleh indeed plans to return to Yemen, it is unlikely that the situation will improve. Many believe the country is likely to descend into civil war, as the originally peaceful, pro-democracy protest movement became a deadly armed struggle between Saleh and the Hashids, the country's largest tribal grouping. However, analysts have suggested to the New York Times that Saudi Arabia may not let him Saleh leave, or otherwise press upon Saleh to cede power while he is there.

Theory #2: Saleh is grievously injured

Supporting evidence. Saleh was scheduled to address the country after he was injured, but only issued an audio message, where his voice sounded "labored." Soon, other sources reported that Saleh had severe injuries, and some Arab news reports said he had pieces of wood embedded in his body, according to the Times. Moreover, Saleh transferred power, albeit on a temporary basis, to Vice President Abd Rabu Mansur Hadi. "If he was seriously injured then he would need long treatment in Saudi Arabia and Yemen cannot stand a protracted power vacuum," said an Al-Jazeera correspondent.

Counter evidence. Yemen's ruling party has continuously played down Saleh's injuries, and said the transfer of power to Hadi is only temporary, reports the Journal.

What this means. If Saleh is injured for quite some time, Hadi will have to maintain power in Yemen, which might leave the country deeply vulnerable to al-Qaeda. According to Gregory Johnson at Big Think, Hadi is not seen as a strong player on the Yemeni political scene - he was named VP after the civil war in 1994 largely as a gesture to the south. Hadi "has neither the ambition or the ability to go after the top post for any extended period of time," writes Johnson. With an active al-Qaeda branch in Yemen, and no clear successor or plan for a transition of power, Saleh’s departure could pose one of the most significant policy challenges for the U.S. in terms of terrorism, the Washington Post indicates.

Theory #3: This is an exit strategy mediated by Saudi Arabia

Supporting evidence. Saudi Arabia has been attempting to ease Saleh out of power for more than a month, according to the Journal, and have been trying to negotiate a deal with him that would proivde him and his family immunity from prosecution in return for voluntarily stepping down. Early Sunday morning, 31 members of Saleh's immediate family also departed the capital for Riyadh, sources told the Journal, leasing to speculation that Saleh had negotiated a "face-saving" deal with Saudi Arabia.

Counter evidence. Saudi officials have maintained Saleh is in the capital for treatment only and that the visit was not a political one. Moreover, Saleh’s son Ahmed, whom he was grooming as a successor, is believed to have stayed behind, according to the Post.

What this means. This puts a tremendous amount of pressure on Saudi Arabia. The U.S. in the past had pressed Saleh to step down, but unlike Saudi Arabia, it did not have enough leverage, according to the Times. If Saudi Arabia indeed negotiated the deal with Saleh, it is left with the responsibility of building a new political order in a divided country, while it continues to face other revolutions through the Middle East. According to an Al-Jazeera correspondent, this is the likely outcome should Saudi Arabia step in:

"The opposition and the tribal establishment will say they are now the ones to dictate a new deal. You have the power tribal leaders, the disenchanted generals who joined the pro-democracy movement and the Islamists who are the most organised and largest opposition party that will definitely sit down and draft a new law about the transition and who should oversee it. Saudi Arabia has leverage, cash, border, and historical political influence. They will talk to tribal leaders, give them money, and instruct them what to do and what the exit strategy is."