Ecuador, Peru, Colombia and Venezuela have been in the news recently for reasons as distinct and independent as the countries themselves. But these four nations -- with a landmass half that of the United States and more than 90 million people -- share a potentially dangerous mix of race and class within a rigid social structure.

Four countries in the northwest corner of South America -- around the Andes Mountains -- are in the news. Ecuador's president was overthrown after having proclaimed dollarization. Colombia has received over $1 billion from the United States to stop leftists. Venezuela's visionary president wants to shake up its lopsided class structure. Peru's iron-fisted president is seeking an unconstitutional third term.

Now these are independent countries that don't particularly care for each other. Yet their troubles arise out of a shared history and rigid social structures that fuel the discontent now rampant among their peoples.

Some 200 years ago, they were all part of the Spanish-ruled vice-royalty of New Granada. And it was that unity that motivated South America's "Great Liberator," Simon Bolivar, who fought hard and brilliantly to realize his dream of a second United States of America.

Not only did Nueva Granada, as a result of the Bolivar revolution, split into four distinct countries, but during most of the 19th century Colombia was torn apart by "la violencia," as it is now. Venezuela was luckier. It held together but under a tough one-man rule, as it is now by Hugo Chavez. So too Peru as it is now by Alberto Fujimori.

History does matter for these countries and, as the situation in Ecuador indicates, social structure also matters. There, Indians have risen as a race against the whites -- not only as whites but also as a class, a political elite that has robbed them of their pensions.

In all of these countries race and class coincide in a social structure so rigid that many despair that any real change will come.

At the bottom in the mountainous regions are Amerindians on the tropical coasts it is Africans. The two peoples are racially distinct but among the poorest of the poor. All four countries have sizable middle classes made up of mixed-race people and immigrants from Europe and Asia. Like the Creoles who launched Bolivar's revolution two centuries ago, many young middle class people today harbor revolutionary hatred of the political elites and social upper classes. They also hate the Yanquis.

The social upper classes and the political elites are distinct. The former generally are light complexioned, the latter much more varied. Those who control the armed forces or parts of them have the power, and power always leads to money. But the social elites, whether national or local, own the land.

Land is what counts. Everywhere in Latin America the Spanish conquerors took vast expanses of land, and most of the land is still owned by the upper classes or parvenu local elites. While Brazil has a different language, history and culture the picture of land ownership is similar -- one percent of the population owns over 90 percent of the land.

In the Andean countries, the narcotics trade has allowed a lot of people, powerful and powerless, to get land. For the poor, growing coca provides enough income to avoid immigrating into the congested cities. For local political elites, drug money allows them to buy land, sometimes a lot of it.

The booming economies of East Asia have shown that development can reduce poverty and create middle classes. But in Latin America, and especially the Andean countries, race comes in to block social mobility.

The result is rigid social structures that seem never to change. Yet, ironically, what may finally bring change are the drug economies. They are now changing land ownership on the ground even while providing new incomes. And yet the U.S. is helping Colombia fight several leftist insurgencies that have gained popular support because things are really changing where they rules.

There is no way America can win its new war in Colombia. At best, Washington can only restore history's rigid status quo. But Venezuelan president Hugo Chavez knows that without big changes in both race and class stratification, the entire Andean region some day soon will relive the despair that broke the body and spirit of Simon Bolivar.

PNS editor Franz Schurmann, professor emeritus of history and sociology at UC-Berkeley, has traveled extensively and reads widely in the Asian, Russian and Arab media.