Editor's note: Daniel Martin Varisco is a professor of anthropology at Hofstra University and has visited Yemen over a dozen times for development consulting and research since 1978. He moderates Tabsir, an academic blog on Islam and the Middle East.
(CNN) -- "Yemen is not Tunisia." These were the words that President Ali Abdullah Saleh spoke to his people on television last Sunday.
As street protests erupt in Yemen's capital, it is not surprising that an Arab leader who has held power since a bloodless coup in 1978 would dismiss calls for his ouster.
But he was correct.
Although his regime has been accused of corruption, Saleh is no Zine El Abidine Ben Ali of Tunisia, nor even Hosni Mubarak of Egypt. Instead of using an iron fist, he has maintained power by cleverly playing off rivalries among tribal, religious and political divisions.
When he became president of North Yemen, he allied himself with Sheikh Abdullah al-Ahmar, who headed the most powerful tribal alliance in the North. After negotiating the unification of Yemen's North with the socialist South in 1990, Saleh fostered a climate of grass-roots democratization before outmaneuvering the socialists for total control of the country.
Power is shared in Yemen largely because of the continuing local importance of tribal affiliation. This is not always understood. A major conflict near Yemen's border with Saudi Arabia, for example, has been wrongly characterized as an Islamist rebellion. Like most political conflict in the region, the battle has religious overtones, but it is mainly over tribal autonomy.
The other internal conflict is a growing secessionist movement in the South, where the standard of living has declined drastically since unification.
Then there is al Qaeda in the Arabian Peninsula, a minor thorn to the Yemeni government, and one that has benefited its military, through stepped up anti-terrorism aid from the United States.
Yemen's regional diversity actually helps a weak central government to remain in power. No rival commands a large enough following to challenge Saleh's rule. The protesters call on Saleh not to put his son in power, but no one is chanting a viable successor's name. There is no ElBaradei waiting in the wings, as we see in Egypt.
The people protesting are not the same, either. Two-thirds of Tunisia's 10.5 million citizens live in cities, but fewer than a third of Yemen's 23.5 million people are urban -- and many of these are recent arrivals from the countryside.
Literacy rates are much higher in Tunisia, along with almost all other measures of the standard of living. Yemen is the poorest country in the Middle East and North Africa, with a per capita gross domestic product of $2,600, compared with Tunisia's $9,500.
The media, from The New York Times to Al-Jazeera, are awash with coverage of street protests as though a wave of pro-democracy sentiment were sweeping the region.
But Tunisia appears to be an exception rather than a harbinger of radical change for Yemen. The protests in Yemen reflect genuine concerns, but they are less about the present government being evil than its being ineffective.
So far the protests in the capital have not resulted in bloodshed, but allowed factions to voice the concerns they have been complaining about in private and with friends. Many Yemenis, looking at the aftermath of regime change in Iraq, prefer the existing government's ability to provide relative security over any new civil strife.
While no one factor brought down Ben Ali in Tunisia, the ability of protesters to coordinate activities is no doubt a key factor. Nine out of ten Tunisians have cell phones, but only one out of three Yemenis do.
A third of Tunisians have access to the Internet, but only one out of ten Yemenis do, and their service is much less stable. Such instant communication can flood the streets in Tunisia, but not so easily in Sanaa.
Given Yemen's pressing economic and environmental problems, no one can predict what the future holds for its present government. But regime change in Yemen is not just a twitter away.
The opinions expressed in this commentary are solely those of Daniel Martin Varisco