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 percent of the world’s population live in just two countries, China and India, each with a billion-plus population. A quarter (26 percent) 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 percent of all people live in fewer than 90 countries. Yet the United Nations has 193 members. Among its most recent recruits are Timor-Leste (pop. 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 million and 45 million? Why do the Catalans not? On Monday, Iraqi Kurdistan vote on independence from Iraq. On 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 (pop. 11,359) is a sovereign state, what is the argument against an independent Kurdistan or Catalonia?