LONDON — The recent independence referendums in Iraqi Kurdistan and Catalonia, and the predictable heavy-handed responses from the central governments in Baghdad and Madrid, have raised many questions — a catechism without answers — on the meaning of nationhood in the 21st century. What is a nation? What is a nation-state? Is it the same as a country? Are a people, or a tribe, the same thing as a nation? In a globalized economy what does national sovereignty really mean?

My guess is most Americans don’t think of these questions. They live in “One Nation Indivisible,” even if their country doesn’t feel that way these days. But “what is a nation?” is a question that has been asked with urgency in many parts of the world in the almost three decades since the end of the Cold War.

Fifteen new/old nations emerged out of the Soviet Union alone. Its European satellites also redefined themselves. Within five years of the fall of the Berlin Wall, East Germany agreed to be effectively purchased by the West Germans. Czechoslovakia became two nations, created out of negotiation. Yugoslavia eventually became seven countries brought forth upon this earth in bloodshed.

Not all groups have succeeded in the push for a nation-state of their own. The Kurds, despite appalling repression, have never stopped trying to create a nation of their own.