As battles in Yemen raged Thursday, the deadly fighting in the streets of the capital between forces loyal to President Ali Abdullah Saleh and members his own tribe highlights some deeply personal faultlines in the crisis.
One of President Saleh's most steadfast allies in a nation of notoriously loose allegiances was the late Sheikh Abdullah al-Ahmar. Before they were political allies, they were friends and as al-Ahmar grew up to head the Hashid tribal federation, Yemen's most powerful, the partnership only strengthened.
But Mustafa Alani, a director at the Gulf Research Center, notes that, critically, the alliance was not passed down to the sheikh's ten sons.
"All the sons of the sheikh are standing against Ali Abdullah Saleh, and this is very important, because Ali Abdullah Saleh is part of the al-Ahmar family," said Alani. "He's from one of the branches from Sanhan, which belongs to the al-Ahmar family. So, we're talking about a major tribal conflict - a major family conflict."
It's a family spat playing out very publicly and at a very volatile time. While tribal allegiances dominate, Yemen is also seeing political protests, part of the Arab Spring, as well as military discontent and growing Islamist ambitions.
Tom Finn, a journalist in Sana'a, describes the part of that mix that's roiling the capital.
"The opposition to President Saleh is huge in Yemen, but it's also hugely divided," said Finn. "The tribes, like the Hashid, have their own grievances against the government which go back a long way, long before any of this unrest started. But the fact that they're fighting in the capital and the fact that this fighting is taking place just a few miles away from Change Square, which is where all these thousands of protesters are camping out, definitely is symbolic."
The fighting between this generation of the al-Ahmar family has left parts of Sana'a devastated, with government troops battling members of the Al-Ahmar clan holed up in what Finn describes as their gothic-style mansion in the east of the city.
Dubai-based analyst Alani says the real problem does not lie with the eldest al-Ahmar brother, Sadeq, the new sheikh and head of the Hashid tribe.
"Sadeq has no political ambition. He is a king maker; he's not a king. But with the third son, Hamid, he basically tried to block any succession process and he put a lot of effort to prevent Ali Abdullah Saleh to pass power to his son, because he thinks he is better qualified than the son of the president," said Alani.
A powerful businessman, Hamid al-Ahmar has influence in a variety of key sectors, including satellite communications. Ignoring his family's own stake in tribal lines of succession, he, like the opposition in Libya and Egypt, objected to perceived attempts at hereditary rule.
Saleh tried to placate his opponents shortly after the protests began in February, vowing his son would not seek the presidency, nor would he run for re-election.
It was not enough. The situation only grew worse when the president three times rejected a regionally-brokered deal to step down sooner.
So far, the tribal fighting has been contained mainly to close loyalists of the al-Ahmar family, and not spread to the wider Hashid federation. The Gulf Research Center's Alani.
"We have to remember that the Hashid is not really throwing all its power against the regime now," he said. "We are witnessing, yes, clashes here and there, but the Hashid has not mobilized all its military muscle. And the reason why is they are not sure. The Hashid is split and now we are talking about a few hundred fighters. But it could go to a few thousand."
Alani says Saleh still holds sway over some Hashid members, while others have renounced their allegiance to the president but so far have not taken up arms.
Journalist Finn says the latter are weighing their options.
"Certainly there are contenders within that tribe who would be involved in the next government in Yemen, whether it would be indirectly, by funding as they are at the moment funding the opposition, or by stepping up and taking governmental positions. There's still fragmented opposition in Yemen, but massively growing frustration from all groups with the president," said Finn.
It's a frustration that threatens to tear apart one of the last seams holding Yemen together.