ON THE WAY TO Mareb, the legendary capital of the Queen of Sheba in North Yemen's eastern desert, there is a road block where soldiers check identity cards and drivers' licences. However, many cars simply leave the road a few hundred metres before the road block and drive around it. Residents described the procedure as typical of the relationship between the people and the authorities in a country where the concept of modern government is still in its infancy.
Outside such major cities as Sana and Taiz, many cars don't even have licence plates, and the turbaned men with machine guns are not government soldiers, but tribesmen whose loyalty often goes to the highest bidder - such as the Government of neighboring Saudi Arabia.
"Few revolutionary regimes in the Middle East can have faced problems of building legitimacy as serious as those confronting the Yemeni republicans," Michael C. Hudson, an expert on Arab politics, has written.
North Yemen is still a largely rural, tribal society, which had no experience in modern government until the Zaidi Sultanate - which had ruled for 1,000 years - was deposed in 1962.
"The vast majority of people in this country live in places where westerners would never get to, unless they hiked there on foot," remarks Paul Martin of the American Institute of Yemeni Studies in Sana. Only now, for the first time, is the government of Colonel Ali Abdullah Saleh conducting a census, since no one really knows how many people there are here: estimates range between six and nearly nine million.
Due to its rural isolation, an Arabic- speaking Western diplomat describes the society as "profoundly xenophobic. North Yemenis want to keep all foreign powers at arm's length. This is in stark contrast to South Yemen, which as a result of British colonialism is more developed educationally and more psychologically able to be pro- Soviet."
In 1839, Britain occupied the South Yemeni port of Aden to establish coal- bunkering facilities for ships sailing to and from India. At the time, the Turks were in nominal control of the mountain regions to the north. The line between the Turkish and British zones eventually became the border separating the two Yemens.
Although the histories of the two countries have been radically different, strong tribal links exist, fostering a yearning for unification. However, the prospects for unity seem no better than that of the two Germanys or the two Koreas.
While the Marxist regime in South Yemen attempts to control most aspects of life, the independent tradition of the mountain people makes it impossible for Col. Saleh to do likewise. Not only are the tribes left alone, but so are the merchants. North Yemen's economy is so unrestrained that a large number of goods available here are the result of open smuggling. Contraband Kellogg's Rice Krispies are on sale in Sanaa's corner groceries.
However, by North Yemen's standards, the Government's ability to govern appears to be increasing. Recent elections for local community councils are said to have undercut the authority of tribal chieftains, because a literacy requirement made many of them ineligible as candidates (illiteracy here is estimated at 90 per cent).
Moreover, as economists here see it, the discovery of oil in 1984 by the Dallas-based Hunt Oil Co. should eventually give Col. Saleh's regime the money to construct more roads and facilities, thus controlling the citizenry more.
The very inability to control the population has been a factor in the country's political instability, shown by four coups and violent upheavals between 1962 and 1978, when Col. Saleh took over, after the previous ruler, Ahmed Ibn Hussein al-Ghasmi, was killed by a suitcase bomb carried by a South Yemeni envoy.
Foreign diplomats give Col. Saleh high marks for remaining in power as long as he has. His foreign policy of "positive non- alignment" is viewed as a success, because it has meant playing one power off against the other and garnering aid from all sides. Although the Soviet Union has contributed $1-billion worth of military assistance since 1980, there is enough Saudi and Western aid to keep North Yemen from falling into Moscow's grip. Still, the Soviet Union is considered the more influential of the two superpowers here.
But due to the January war in South Yemen, the Sana Government has evidently found itself in a sensitive position. More than 10,000 people were killed in the fighting in the capital of Aden, in which president Ali Nasser Mohammed was toppled by a more hard-line Marxist faction.
Col. Saleh supported Ali Nasser, but observers here suggest that Col. Saleh will have no choice but to come to terms with the new Aden regime, owing to South Yemen's ability to make trouble in the north when it sees fit.
Full-scale war between the two Yemens occurred in February and March of 1979 and sabotage across the rugged frontier would be easy if relations suddenly worsen.
A tempting target might be a new oil refinery, to open this spring, in the desert east of Mareb, not far from the South Yemeni frontier. In the past, upheavals in one Yemen have often led to upheavals in the other.