“The people of South Sudan, for the first time since 1898, are going to determine their own future,” declared Barnaba Marial Benjamin, southern Sudan’s information minister, before last month’s referendum on the region’s independence. “In fact, it will be the last-born state on this continent of Africa.” If he meant that no more African countries will split up, however, he was probably wrong.

It’s natural to be suspicious of referendums that produce ‘yes’ votes of almost 99 per cent, but in this case it was a genuine expression of southern opinion. The new state will become independent on July 9, and so far it looks like the erstwhile government of undivided Sudan will accept the outcome peacefully. After decades of war between the Muslim, Arabic-speaking north and the very different south, where most people speak local languages and are Christian, division makes sense. But it also creates a precedent.

That fount of wisdom on geopolitical affairs, Libyan strongman Muammar Gaddafi, warned a meeting of African and Arab leaders last October that southern Sudan’s independence would spread like a “disease… to all of Africa.... With this precedent, investors will be frightened to invest in Africa.” But the African Union has blessed the split, while emphasizing that this is a special situation and an exception.

It is a very special situation. About two million people have been killed in Sudan’s 43 years of civil war, the majority of them southerners. As a result of the endless fighting, southern Sudan is one of the least developed regions in the world. The southerners deserve their independence — but the implications are vast.

Etched in blood

If it’s okay to split up Sudan, what’s to stop other secessionist groups from launching wars of independence, knowing that if enough people are killed they will probably get their way in the end? How about Nigeria? The oil-rich southeastern region (Biafra) has tried that once already. The Congo? There was once a war, backed by Western mining interests, for the independence of the province of Katanga.

The rot has already spread beyond Africa. The decision in 2008 by the Nato countries and some others to recognize the independence of Kosovo, which was still legally a province of Serbia, created a similar precedent in Europe. In fact, it is an even more sweeping precedent, because the Serbian government, unlike the Sudanese, did not assent to the separation. If Kosovo’s independence can be recognized without Serbia’s agreement, why can’t Turkish-majority northern Cyprus become legally independent without the permission of the Greek Cypriot- dominated government in Nicosia? Why can’t the breakaway bits of Georgia be recognized as independent states? Why can’t there be an independent Kurdish state?

Why not hold the long-denied plebiscite in divided Kashmir, and let the local people decide whether they want to be part of Pakistan, or part of India, or independent? Why can’t the western half of New Guinea separate peacefully from Indonesia? Why can’t Tibet and Xinjiang hold referendums on independence from China?

The sum of human happiness would probably be increased if these ethnically distinct areas got to choose their own futures, and it is not necessarily true that changing the borders would be a bloodier business than keeping them frozen in place. Conflict is still possible between Sudan and South Sudan, especially over the sharing of the oil revenue. Most of the oil is in the south, but the pipelines take it out through the north. So far, however, both sides are behaving in a very grown-up way, and together they are an advertisement for the virtues of letting borders change.