" Famine in South Sudan." When I was growing up in the 1970s, it would have been an unremarkable headline. In those days, we were horribly habituated to images of African kids with matchstick legs and bloated bellies. Now, though, such headlines are startling, and for the best of reasons: Famines are slowly being eradicated.

According to the Danish academic Bjorn Lomborg, 1.7 million children died from malnutrition in the first decade of this century. A shocking number, to be sure; but it had fallen by 60 percent since the 1950s, despite the world population more than doubling in that time.

As usual, few saw the good news coming. "The battle to feed all humanity is over," wrote Paul Ehrlich in 1968. "Hundreds of millions are going to starve to death." In fact, when he wrote those words, hunger was already in retreat. New strains of cereals, resistant to parasites and capable of growing at broader latitudes, were transforming food production. Chemical fertilizers enabling vast gains in yield. No less important, countries which had pursued "food security" as a paramount policy goal began to open up their economies, buying at world prices and so, paradoxically, making their food supplies more secure.

When Ehrlich was writing, the United Nations classified 29 percent of the world population as undernourished – down from 50 percent immediately after the Second World War. Today, that proportion has fallen to 11 percent.

So what has gone wrong in South Sudan? The usual thing: misrule. Since the 1990s, if not before, there has been a superabundance of food in the world. But plenty is no guarantee against rapacious, brutal, corrupt regimes. Almost every recent outbreak of starvation has been caused by bad government or by war. The last 20 years have seen famines in Ethiopia, the Democratic Republic of the Congo and Sudan — all caused by conflicts. There may have been an even worse spasm of starvation in North Korea in the end of the 1990s (we can't be sure of anything in that secretive tyranny) caused, not by war, but by an insistence on economic self-reliance of the sort which, incredibly, some Western protectionists want to imitate.

South Sudan, which broke away from Sudan in 2011, has followed the post-independence script to the letter: corruption, autocracy, tribal violence, civil war. President Salva Kiir is from the largest ethnic group, the Dinka. Since the end of 2013, he has been chronically at war with his former deputy, Riek Machar, who is from the second ethnic group, the Nuer. It would be like some comically dark Evelyn Waugh novel if it were not so tragic. Supporters of both men attack members of the other tribe; planting and harvesting are disrupted; humanitarian food supplies are blocked.

At the risk of sounding trite, what South Sudan needs is a minimally competent administration. The days when starvation was caused by drought or crop failure are almost over. Modern starvation is caused by politicians. The worst famines of the past century — 10 million died when Stalin collectivised Ukrainian farming in the 1930s, more than 20 million when Mao did the same to China in 1959 — were inflicted on people by the coercive power of the state.

South Sudan is no different. "This crisis is man-made," said State Department spokesman Mark Toner, "the direct consequence of a conflict prolonged by South Sudanese leaders who are unwilling to put aside political ambitions for the good of their people." Quite.

The solution to famine, strange as it sounds, is democracy. The great Indian economist Amartya Sen points out that mass starvation has existed under every other system of government: theocracy, absolute monarchy, fascism, communism. But never in a state that is accountable to its citizens at the ballot box.

Obviously, it is not in our gift to impose democracy on other nations, only to inspire by our example. So, short of invading and recolonizing South Sudan, which no one wants, is there anything we can do to help?

Two things — both, as it happens, are completely cost-free. First, we can stop propping up hopeless governments with aid. If those governments are the problem, then giving them a financial lifeline simply prolongs their people's suffering. Second, we can open our markets to African exports. The United States, like the EU, places all sorts of obstacles in the way of products from developing states, especially food and textiles. Scrapping those restrictions will make our own citizens, as well as theirs, better off. It's not much, but it's something.

Dan Hannan is a British Conservative MEP.