Yemeni protesters inspired by unrest in Tunisia, Egypt and elsewhere are demanding an end to president Ali Abdullah Saleh's long rule, but peaceful change looks unlikely in a tribal land mired in conflict and poverty.
At least 16,000 demonstrators took to the streets in Sanaa today in the biggest of a wave of anti-government protests this month, echoing the Arab ferment touched off by the popular overthrow of Tunisian president Zine al-Abidine Ben Ali.
"People are upset. They want Saleh to leave. He's been in power for 33 years and has destroyed the country," said Abdullah al-Faqih, a political science professor at Sanaa University.
Secular Tunisia, with its relative wealth, educated middle class and absence of regional or religious cleavages, offers many contrasts to Yemen, a deeply Muslim society riven by southern separatism and a recent war with northern rebels.
"The Yemeni socio-political context is fiercely tribal," said Khaled Fattah, an expert on Yemen and state-tribe relations in the Arab world at Scotland's St Andrews University.
"The keys to any major political change in Yemen are not in the hands of unions and political parties, but influential tribal leaders and members of the Saudi royal family."
Neighbouring Saudi Arabia, worried by instability in Yemen where an al-Qaeda network has taken root, helps bankroll Saleh, but also maintains independent ties with some Yemeni tribes.
Yemen is in far worse economic shape than Tunisia or Egypt, but popular grievances in all three nations focus on high prices and unemployment, along with high-level corruption and misrule.
Unemployment in Yemen is in the 35 per cent range and one third of Yemen's 23 million people now live below an absolute poverty line defined as access to 1,200 calories per day.
Although Saleh's two predecessors were assassinated, the last two power transitions in Yemen were arranged smoothly by the military, including the one which brought him to office in 1978.
A master of clan and tribal politics, Saleh has survived many stern challenges, including an attempted secession by the south in 1994, only four years after unity with the north.
But the money he needs to keep tribes and soldiers loyal is diminishing. Rapid population growth has coincided with a decline in the modest oil revenue that makes up 70 per cent of Yemeni government revenue and 90 per cent of exports.
The president has responded to the latest unrest by denying he will seek another term in 2013 or will try to hand power on to his son. He has also promised to raise the salaries of civil servants and military personnel by at least $47 dollars a month.
When protesters toppled Tunisia's Ben Ali, no foreign power stood up for the ousted ruler. Saleh, by contrast, is viewed by the West as a vital ally in the struggle against al-Qaeda.
Some still hope that Saleh himself can organise a peaceful transition and spare Yemen a descent into bloody chaos.