When the Jidaan tribe in the mountains of central Yemen were angry that they weren't getting enough lucrative government jobs, they engaged in what passes for the normal political process here: Their gunmen seized the main highway and hijacked fuel trucks supplying the capital.
In battles last week with police trying to open the road, at least one tribesman and three policemen were killed, a repeat of clashes the previous month, and the month before. Each round of fighting brings negotiations as the government tries to build an alliance and the Jidaan seek concessions.
Multiply that process across Yemen's hundreds of tribes and clans, and the result is low-level violence nearly every week somewhere in the country, with electrical lines getting cut, roads blockaded or even bombs going off at police stations.
Government authority has traditionally been weak or even nonexistent in some areas of Yemen, but rarely as much as it seems now. That could have serious consequences for Yemen and its main Western backer, the United States, which needs a stable regime to fight against a dangerous al-Qaida presence.
President Ali Abdullah Saleh has held power for 32 years in Yemen, the Arab world's poorest nation, by deftly manipulating its multiple tribes and factions, passing out money, development projects and jobs to keep tribes in his pocket and using divide-and-rule tactics to pressure opponents.
Now his elaborate strategy may be unraveling, critics and experts warn _ not least because oil revenues are falling, reducing his ability to buy supporters.
For Yemen, that could mean total chaos or even fragmentation. For the United States, it could mean the weakening or loss of a key partner in the fight against al-Qaida, allowing the terror group to deepen its roots in a country strategically located near vital shipping lanes and some of the world's largest oil and gas fields in the nearby Persian Gulf.
Yemen's tribes have always been highly independent, all but running large parts of the country. But they appear to be growing increasingly bold in defying the central government. Disgruntled tribes have given sanctuary to al-Qaida militants, and months of pressure and cajoling by San'a have brought little sign they're willing to turn them in.
At the same time, Saleh has to deal with a growing secessionist movement in the south, which was once an independent nation and where some feel that unity since 1990 has imposed an "occupation" by northerners. A years-long civil war with Shiite rebels in the north, though calm for the moment, has the potential to erupt again.
Saleh's growing alliance with Washington against al-Qaida is also hurting his standing at home, where resentment of the West, fear of foreign domination and religious conservatives run deep.
Tribes in central Marib province were infuriated when a May airstrike, intended to target al-Qaida militants, accidentally killed the province's deputy governor, a prominent local tribal figure. Angry tribesmen clashed with the army, and bitterness lingers: In early October, a group of Marib tribes sent a delegation to the leader of the northern Shiite rebels in a show of support that was seen as a slap to Saleh.
Al-Qaida militants have also become bolder, staging deadly attacks against security offices, police and army personnel. On Oct. 12, al-Qaida's affiliate in Yemen said it was setting up a "new army" to overthrow Saleh's regime.
Meanwhile, the San'a regime's credibility is undermined by rampant corruption, which leaves many tribes feeling out in the cold when their areas are left without development projects or jobs.
"The future of Yemen hinges on wisdom and dialogue," said Sheik Jaabal Tayman, an opposition lawmaker and tribal chief from Marib. "Without them, our future will be bleak."
Saleh's party is trying to negotiate a national consensus agreement with opposition parties, but talks have made little headway. The opposition demands profound political change, including reduction of the president's powers and guarantees of fair elections, while Saleh is offering only limited electoral reforms.
But Saleh wants a deal to bolster his regime's credibility. His ruling party's majority in parliament is expected to be significantly reduced in elections scheduled for April 2011, because of worsening poverty and southern resentment.
"Anyone in power needs legitimacy to continue in power ... half a legitimacy is better than none," said Yasser al-Awadi, a senior lawmaker close to Saleh. "We cannot even dream of winning 240 of parliament's 300 seats again."
National consensus would also give Saleh some cover for his plans to amend the constitution to allow him to run for a third consecutive 7-year term in 2013. Currently, constitutional provisions in place since 2001 allow only two consecutive terms.
But the failure to reach a deal worries the Americans, who want an agreement to boost stability.
In a sign of the concern, America's third-ranking diplomat, William Burns, held a rare meeting with opposition leaders this month.
"The United States certainly strongly continues to support the democratic process in Yemen, not only a genuine national dialogue, but also free and fair parliamentary elections," he said in San'a on Oct. 6.
Like many other Arab leaders, Saleh looks to his family to protect his back.
His oldest son Ahmed, who many believe is being groomed to succeed his father, commands the elite presidential guard and the special forces. Saleh's stepbrother, Mohamed Saleh al-Ahmar, leads the air force, where another, younger Saleh son, Khaled, serves. One nephew commands Central Security, a paramilitary force used in part to deal with domestic unrest, and another is deputy head of the National Security Agency, an intelligence body.
"Many of the problems we suffer from in Yemen are made by the political elite as they fight for power and authority," said Yemeni analyst Abdel-Ghani al-Iryani.
Associated Press correspondent Ahmed al-Haj in San'a contributed to this report.