This is a country laden with oil, diamonds, Porsche-driving millionaires and toddlers starving to death. New Unicef figures show this well-off but corrupt African nation is ranked No. 1 in the world in the rate at which children die before the age of five.

“Child mortality” is a sterile phrase, but what it means here is wizened, malnourished children with twig limbs, discolored hair and peeling skin. Here in Lubango in southern Angola, I stepped into a clinic and found a mother carrying a small child who seemed near death. He was unconscious, his eyes rolling, his skin cold and his breathing labored, so I led the mom to the overburdened nurses.

Just then, 20 feet away, a different mother began screaming. Her malnourished son, José, had just died.

Westerners sometimes think that people in poor countries become accustomed to loss, their hearts calloused and their pain numbed. No one watching that mother beside her dead child could think that — and such wailing is the background chorus in Angola. One child in six in this country will die by the age of five.

That’s only the tip of the suffering. Because of widespread malnutrition, more than one-quarter of Angolan children are physically stunted. Women have a 1-in-35 lifetime risk of dying in childbirth.

In a Lubango hospital, I met a 7-year-old boy, Longuti, fighting for his life with cerebral malaria. He weighed 35 pounds.

His mother, Hilaria Elias, who had already lost two of her four children, didn’t know that mosquitoes cause malaria. When Longuti first became sick, she took him to a clinic, but it lacked any medicine and didn’t do a malaria test. Now Longuti is so sick that doctors say that even if he survives, he has suffered neurological damage and may have trouble walking and speaking again.

Yet kids like Longuti who are seen by a doctor are the lucky ones. Only about 40 percent to 50 percent of Angola’s population has access to the health care system, says Dr. Samson Agbo, a Unicef pediatrics expert.

Angola is a nation of infuriating contradictions. Oil and diamonds give it a wealth that is rare in sub-Saharan Africa, and you see the riches in jewelry shops, Champagnes and $10,000-a-month one-bedroom apartments in the capital, Luanda.

Under the corrupt and autocratic president, José Eduardo dos Santos, who has ruled for 35 years, billions of dollars flow to a small elite — as kids starve.

President dos Santos, whose nation’s oil gives him warm, strong ties to the United States and Europe, hires a public relations firm to promote his rule, but he doesn’t take the simplest steps to help his people. Some of the poorest countries, such as Mauritania and Burkina Faso, fortify flour with micronutrients — one of the cheapest ways possible to save lives — yet dos Santos hasn’t tried that. He invests roughly three times as much on defense and security as on health.

“Children die because there is no medicine,” lamented Alfred Nambua, a village chief in a thatch-roof village on a rutted dirt road near the northern city of Malanje. The village has no school, no latrine, no bed nets. The only drinking water is a contaminated creek an hour’s hike away.

“Now there’s nothing,” said Nambua, 73, adding that life was better before independence in 1975.

“In the colonial period, when I was sick, they were afraid I would die and gave me good care,” he said, and he pretended to shiver in imitation of malaria. “Now when I’m sick, no one cares if I die.”

Statisticians say that Angola’s child mortality is, in fact, declining — but achingly slowly.

“Death in this country is normal,” said Dr. Bimjimba Norberto, who runs a clinic in a slum outside the capital. A few doors down, a funeral was beginning for Denize Angweta, a 10-month-old baby who had just died of malaria.

“If I lived in another country, I could still be playing with my daughter,” Denize’s father, Armondo Matuba, said bitterly.

It may get worse. With falling oil prices, the government has proposed a one-third cut in the health budget this year.

I’ve often criticized Western countries for not being more generous with aid. Yet it’s equally important to hold developing countries accountable.

It’s difficult to see why Western countries should continue to donate to Angola and thus let rich Angolans off the hook as they drive Porsches.

There are many ways for a leader to kill his people, and although dos Santos isn’t committing genocide he is presiding over the systematic looting of his state and neglect of his people. As a result, 150,000 Angolan children die annually. Let’s hold dos Santos accountable and recognize that extreme corruption and negligence can be something close to a mass atrocity.