Niall Ferguson is the Laurence A. Tisch professor of history at Harvard University. His new book, The Square and the Tower, will be published by Penguin on Oct. 5
We were promised a world without borders. In 1990, the Japanese management consultant and business-school professor Kenichi Ohmae published The Borderless World, in praise of global supply chains. In 1996, John Perry Barlow penned his Declaration of the Independence of Cyberspace, addressed to the "governments of the industrial world." He told them defiantly: "Cyberspace does not lie within your borders."
Just over two decades later, borders are back. In his speech last week to the United Nations General Assembly, Donald Trump was unequivocal: "We must uphold respect for law [and] respect for borders."
Like President Trump's reference to the North Korean dictator, Kim Jong-un, as "Rocket Man" and his threat to "totally destroy" Mr. Kim's country, this was calculated to appeal to the people Steve Bannon calls "globalists." Yet Mr. Trump's assertion of national sovereignty was one of the few lines in the speech that won applause.
The world itself is not in a globalist mood. Brexit is about reasserting sovereignty, above all over immigration. And Mr. Trump himself clings to his election promise to build a wall along the U.S.-Mexican border, as well as to exclude from the United States the citizens of mainly Muslim countries associated with terrorism.
European elites sneer compulsively at Mr. Trump, but polls show that majorities of their citizens would support a similar ban on Muslim immigration into the EU. Meanwhile, the same European elites are ramping up their efforts to tax and regulate the principal beneficiaries of the borderless world, the giant American tech companies of Silicon Valley.
Yet when you reflect for a moment on the back-to-borders movement, you see how strange the world is. Nations are not like individual humans, normally distributed in size along a bell curve. More than 36 per cent of the world's population live in just two countries, China and India, each with a billion-plus population. A quarter (26 per cent) live in 11 countries with populations in the hundreds of millions. And another third live in 75 countries with populations in the tens of millions. In other words, 95 per cent of all people live in fewer than 90 countries. Yet the United Nations has 193 members. Among its most recent recruits are Timor-Leste (population: 1.3 million) and Montenegro (629,000).
Why is this? Why do the Kurds not yet have a nation state with borders of their own, despite numbering between 30 and 45 million people? Why do the Catalans not? On Monday, Iraqi Kurdistan will vote on independence from Iraq. In six days (Sunday, Oct. 1), Catalonia will vote on independence from Spain. Neither referendum is seen as legitimate by the states from which Kurds and Catalans would secede. Yet if the tiny Pacific island of Nauru (population: 11,359) is a sovereign state, what is the argument against an independent Kurdistan or Catalonia?
Or what about the Rohingya, the Muslim minority in Burma whose plight has attracted the world's attention? Would Aung San Suu Kyi's critics cheer if she proclaimed the independence of Rohingyastan (a country as likely to come into existence as "Nambia," the African state invented by President Trump last week)?
The explanation for all these anomalies is history. Small countries can attain independence where the strategic stakes are low. Otherwise, in the immortal words of Thucydides's Melian dialogue, "The strong do what they can and the weak suffer what they must."
The modern world order is not fair. There are nearly as many Indians as Chinese, but only China enjoys permanent membership of the UN Security Council. There are more Germans than French or British citizens, yet it is France and Britain that are members of the "P5," along with the two superpowers of the mid-20th century, America and Russia. Like the five great powers that dominated Europe after the Congress of Vienna, the five permanent members owe their privileged status to history: to past victories, or past alliances that compensated for defeat.
Nevertheless, despite no fewer than 18 resolutions since Pyongyang began its quest to acquire nuclear weapons 24 years ago, the Security Council has yet to impose its will on North Korea (population: 25 million), a medium-sized state that ranks between Madagascar and Australia in the league table of size. Last week's tough talk – Rocket Man retorted by calling Mr. Trump a "mentally deranged U.S. dotard" – took the world another step closer to a day of reckoning. The other members of the P5 are waking up to the possibility that Mr. Trump has a real, if risky, military option, and is capable of using it.
In the final analysis, borders are a function of power. If you can't defend them, they are just dotted lines. The Kim dynasty's calculation has been that nukes are the ultimate border guards. We shall soon find out if that calculation was correct. If so, many more states will want them. If not, we shall be back in the 19th century, when the great powers played their great game with everyone else's borders.
©Niall Ferguson/The Sunday Times, London