SANAA // The accusation this week that Ali Abdullah Saleh rigged the 2006 elections to remain in power is yet another blow to the Yemeni president's credibility.
The source of the allegation, which the government hotly denied, is hardly unimpeachable: General Ali Mohsen Al Ahmar is one of Mr Saleh's main foes after defecting to the opposition in March.
Yet it is a signal that the general, who was the president's closest aide until his defection, has not run out of ways to challenge Mr Saleh's insistence that only he is qualified to usher Yemen through its political crisis.
"Mohsen has sent a message that . . . he has got a lot of cards to play," said Abdulbaki Shamsan, a professor of political sociology at Sanaa University. "He wanted to send a message to Saleh that the legitimacy he is claiming to have is fake."
The prospect of Gen Al Ahmar disclosing more details of his shared past with Mr Saleh will not be warmly received in the presidential palace.
For more than three decades, the general, 66, helped keep Mr Saleh in power by cultivating close ties with all sectors of the military, as well as tribal and Islamist groups.
He played a key role in the crackdown on the socialists during the 1994 civil war and in brokering the union of North and South Yemen in 1990.
He also spearheaded the government's attempts to quell the Shiite Houthi armed uprising which started in 2004.
"Because of his contacts and strictness, he was sometimes a firefighter for the regime, resolving tribal conflicts here and there, as well as confronting Saleh opponents," said Ahmed Al Zurkah, an independent analyst.
Gen Al Ahmar's relationship with Mr Saleh began to sour several years ago over the general's rivalries with two of the president's sons, both commanders of key Yemeni military units and presumptive heirs to the presidency.
According to an account in a US diplomatic cable leaked to WikiLeaks, Mr Saleh tried to have Gen Al Ahmar killed in 2009 by telling Saudi Arabian forces that a home belonging to him was a hideout for Houthi insurgents. The home was attacked by Saudi aircraft.
Whether Gen Al Ahmar walked away from the president or was pushed, his break from Mr Saleh has not been uniformly well-received by government opponents.
Some doubt his motives and believe his defection is an attempt to escape possible prosecution for crimes he may have committed while working with Mr Saleh.
Others, such as Majed Al Madhaji said the general and tribal groups have "hijacked" what was a broad-based, predominantly youth-oriented protest movement. The conflict in Yemen, they say, has become a war among factions of the Saleh regime, with youth sitting on the sidelines.
"Ali Mohsen is using the same old tactics of buying loyalties against which Yemen has revolted. His troops have paralysed the mobility of the protesters by restricting them to a protest camp in central Sanaa. He has given a military face to our revolution," said Mr Al Madhaji.
Yet his defenders say his defection has divided the army and prevented it from acting full-square on behalf of the regime in cracking down on protests.
Equally significant, it has fragmented a regime built on buying the loyalty of the country's tribes and military. For example, the powerful Sanahan tribe, in which Gen Al Ahmar is an influential figure, has withdrawn its support for Mr Saleh, Mr Al Zurkah noted.
"Without Ali Mohsen and the tribes, the youths would not have been able to stand and continue their revolt for months. The army now has no national identity," Prof Shamsan said.
As for the claim that Gen Al Ahmar defected to the opposition to escape prosecution, Mr Al Zurkah, the analyst, argued that he could have merely resigned and fled the country if that were the case.
Instead, he suggested, the general "wanted to atone for his mistakes in his work with Saleh, who abandoned his traditional allies for the sake of his plan to succeed power to his son," he said.
No matter what Gen Al Ahmar does in his very personal struggle with the Yemeni president, it will not be enough to appease activists such as Mr Al Madhaji.
"When we took to the streets, our objective was to overthrow the regime, not just Saleh and his sons. He and Al Ahmar family will be the next battle we will have to fight."