When South Sudan gained independence in 2011, there was great optimism both inside and outside of the country that it was putting its deeply troubled past behind it.

For generations, the South Sudanese had been terrorized by rebel armies and repressive government soldiers. At independence, South Sudan was one of the poorest nations in sub-Saharan Africa but also one of its most oil-rich.

The honeymoon for the world's newest nation didn't last long. Late in 2013 the president and vice president took up arms against each other. And things went downhill fast from there.

"It's the worst I've ever seen and the worst I've ever experienced," says Emma Drew, the humanitarian program manager for Oxfam in South Sudan, who's worked there for eight years. The brutal civil war left tens of thousands of South Sudanese dead, drove more than 2 million people from their homes and lay to waste entire towns.

Aid groups and the U.N. warn that the country is now on the brink of a catastrophic food crisis. One analysis predicts that 40,000 people face starvation. Drew says that dire prediction sounds reasonable to her.

"Absolutely. 100 percent. Yup." She worries not only about those 40,000 "but also the hundreds of thousands that are just one step below," she says.

A peace accord signed in August of 2015 is supposed to bring the leaders of the two warring parties, President Salva Kiir and his former deputy Reik Machar, back together in a unity government. But progress toward that unity government has faltered.

As Kiir and Machar (who's in exile in Ethiopia) bicker, sporadic violence continues across the country along with hyperinflation and massive food shortages.

The conflict has also destroyed crops, driven farmers off their fields and hampered production at South Sudan's oil fields.

The country has some of the largest oil reserves in sub-Saharan Africa, yet nearly a third of South Sudan's population is now dependent on international food aid to survive.

Unlike the devastating drought that's plaguing neighboring Ethiopia, Drew at Oxfam says, the current crisis in South Sudan is a direct result of the war.

"Everything has to be rebuilt," she says. "Markets have been destroyed. Supply lines have been broken. We have to start from scratch."

Inflation is running at 300 to 400 percent. There's a dire shortage of hard currency. Oil production has plummeted, and most of the economy has collapsed.

When South Sudan broke away from Sudan five years ago, it was pumping more than 300,000 barrels of oil a day. Oil exports provided 98 percent of the government's revenue.

Fighting shut down some of the wells. And now because of the drop in global oil prices, South Sudan is losing money on every barrel it pumps. The problem is that South Sudan is landlocked, and its former adversary, the government in Khartoum, is charging $25 a barrel to ship crude through its pipelines to the Red Sea.

With oil trading at just above $30 a barrel, South Sudan's primary export isn't worth exporting.

In an open-air market in the capital Juba, traders say the economic crisis is worsening every week. Prices are rising and people have less money to spend.

Victor Steven, who's 45, sells palm-size plastic bags filled with cooking oil and sugar from a table he has set up in the street.

"There's no money for two months now," he says. "Even the people here in the central government have no money. Their pockets are empty. People are really suffering."

Steven is selling paper cones of salt no larger than a thimble. A few tomatoes are stacked in a modest pyramid on his counter. Customers, he says, are buying less and less.

"Since the beginning of this month, the prices have gone up, up, up, up," he says.

The problem, he says, is the war. South Sudan needs a definitive end to its civil conflict before it can solve any of its other problems.

"If the peace comes, everything will improve very well, yeah," he says.

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