Author Thomas Keneally won the Booker Prize in 1982 for Schindler's Ark, later made into the film Schindler's List. His latest book Three Famines examines three historical famines and their causes.

(CNN) -- Imagine if long-term drought were to strike a part of the rural United States, Wyoming say, or Montana.

There would be bank foreclosures as the price of cattle would fall because there was too many of them on the market, families would tragically lose their farms, and grocery lists would be trimmed.

But would people starve, actually waste away until their bodies began to devour themselves?

In Southern Somalia, Djibouti, parts of Ethiopia and in refugee camps in Kenya at the moment, up to 12 million people, basically half a Canada, are facing death.

In Somalia, the people already in crisis number about four million. Mothers, for example, are again making the Sophie's choice of how to share the small resources of remaining food amongst their children.

And the tired old terms to explain it all are again repeated. The cause, we are told, is drought. The "caused by drought" formula is not only lazy journalism. We've heard that song sung so often in the past that it may now make us immune to the famine's claim on us.

Certainly, drought is a trigger of famine. And global warming might be extending the length of droughts. But Amartya Sen, the Nobel Prize-winning economist famously said that no substantial famine has ever occurred in a liberal democracy. I believe Sen is right.

Famines occur in places where people are tyrannized over either by governments or, in the case of Southern Somalia, by private armies and militias. They occur in places where even in the lead-up years to famine, farmers are not always able to plant crops with security, without the likelihood that they might be confiscated, or that the village granary will be burned by armies, private and government.

Famines, above all, occur in places where people get by on a few food items. Though in the cities, including Mogadishu, Somalia, people might eat canned food and a range of other food, for farmers in East Africa, the normal foods are lentils and the bread made out of dhurra, millet or a grain named teff.

If the grain crop is destroyed by drought or locusts or undue human intervention, there goes the chief nourishment.

The coastal fishermen of Somalia are themselves reduced in what they can eat because the price of grain is escalating out of their reach. The semi-nomadic people who own cattle have a diet of milk and meat. The livestock die for lack of pasture, are stolen or have to be sold or eaten, and there goes life.

In liberal democracies, as much under pressure as they might be at the moment, if one food source is removed from us, we have the ability to turn to another. Not so for the 12 million the U.N. has declared in immediate peril of starving.

So the question arises: Why are people on Earth now, in the 21st century, still surviving on one staple -- just as the Irish did with the potato in the 1840s?

Governments maintain unjust systems of land tenure, that is one reason. Governments put money into arms instead of into infrastructure -- into roads, for example, by which aid can easily transported, or into storage facilities.

One is entitled to ask why, after all the development and emergency aid spent on Ethiopia, there is a food crisis there every time there is a drought? Is this a failure of rain or a failure of government?

We see the above-mentioned "undue human intervention" in East African people's welfare in the fact that in the case of Southern Somalia, the Obama administration has had to give aid agencies a guarantee of freedom from prosecution even if some of the aid has to be given, virtually as a protection bribe, to the fundamentalist military group called Al Shabaab.

Al Shabaab has preyed on the Southern Somalis year after year. Charities must pledge their best efforts to prevent Al Shabaab from hoarding food and charging tax on it.

These realities of famine are as much, if not more, the cause of famine than natural disaster. In some cases it is misgovernment, and in the case of Somalia it is warlord-ism.

The question arises, should this reality stop us from coming to the aid of our fellow world citizens in East Africa? In my opinion it makes it more urgent.

As the old aid song from the 1980s goes, "We are the world." In the meantime we'll only learn to understand and address this deadly phenomenon if we stop citing "caused by drought" every time something like this calamity comes to our notice.

The opinions expressed in this commentary are solely those of Thomas Keneally.